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Modified TDAE petroleum plasticiser

  • Stefan Ptak EMAIL logo , Wojciech Krasodomski , Janusz Jakóbiec and Artur Antosz
Published/Copyright: September 9, 2021
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Open Chemistry
From the journal Open Chemistry Volume 19 Issue 1

Abstract

Petroleum plasticisers are applied as softening additives in rubber vulcanisation processes and as components of rubber mixtures in the production and vulcanisation process. They contain polycyclic aromatic compounds exhibiting carcinogenic and mutagenic effects. Since 2010, the European Union has banned the use of high-aromatic DAE plasticisers. The petroleum industry and tyre manufacturers are developing new types of petroleum plasticisers. The best alternative to the DAE is the TDAE plasticisers, obtained mainly by selective solvent refining. The solvent dewaxing process of classic TDAE plasticisers was studied in order to improve the chemical composition as well as the rheological and low-temperature properties of deparafinate. This article presents the results of an examination of the TDAE plasticiser samples subjected to solvent dewaxing process on a laboratory scale with three types of solvents, MEK–TOL, MEK–MIBK and MEK–MTBE. It was demonstrated that solvent dewaxing of the TDAE plasticiser with positive pour points maintains good process selectivity and allows for a significant reduction of the plasticiser pour point, thus improving the rheological and low-temperature properties. In all dewaxing attempts, the pour point in the deparaffinate decreased significantly to the range −12 to −22°C, compared to the positive pour points of the raw materials. The application tests for two types of the TDAE plasticisers, used to produce oiled rubber and a standard rubber compound, meet the quality requirements for those products.

Keywords: petroleum plasticisers; TDAE plasticisers; solvent dewaxing; polycyclic aromatic hydrocarbons; rubber mixtures

1 Introduction

Petroleum plasticisers are applied as softening additives in rubber vulcanisation processes, in particular for the synthetic styrene–butadiene rubber (SBR), and as components of rubber mixtures in the production and vulcanisation processes. The global elastomer market is dominated by two types of rubbers, namely the natural rubber and SBR, which account for 70–75% of the global elastomer market segment, especially in applications such as car tyres including treads [1]. The annual demand for petroleum plasticisers in 2010 [2] was 1.3 million tons (Figure 1).

Figure 1 Global, annual demand for petroleum plasticisers as per regions of the world.
Figure 1

Global, annual demand for petroleum plasticisers as per regions of the world.

Petroleum plasticisers for the rubber industry are required to meet a number of requirements arising from the specific nature of manufacturing processes and operating conditions of rubber products, which are in particular:

  1. to have the chemical composition required for a given application and have appropriate physiochemical properties;

  2. show sufficient compatibility with the rubber used;

  3. exhibit low volatility in the rubber production process conditions and in production and vulcanisation of rubber mixtures;

  4. have no toxic effects [3], especially no carcinogenic effect [4,5,6,7].

Petroleum plasticisers are classed as petroleum agents [8] used in the production of rubber and gum products. As a rule, the plasticiser used in SBR rubber compositions is referred to as filler oil, which consists of hydrocarbon molecules containing 25–35 carbon atoms.

Petroleum plasticisers are divided into aromatic, naphthenic, and paraffinic ones, depending on the percentage of carbon in aromatic, naphthenic, and paraffinic structures [9].

One of the petroleum plasticiser classifications is based mainly on the methods of production. It distinguishes the following types of plasticisers [10,11]:

  • DAE (distillate aromatic extract) – an aromatic extract obtained from a petroleum vacuum distillate. It has been in use by tyre manufacturers for a long time because of the low cost and high compatibility with SBR rubber [12,13,14,15,16].

  • TDAE (treated distillate aromatic extract) – a modified aromatic extract from a petroleum vacuum distillate;

  • MES (mild extraction solvates) – raffinate of mild solvent extraction of petroleum vacuum distillate;

  • RAE (residual aromatic extract) – an aromatic extract obtained from DAO (Deasphaltisate) in the production of Brighstock;

  • TRAE (residual aromatic extract) – a modified aromatic extract obtained from DAO in the production of Brighstock;

  • NAP (naphthenic plasticisers) – raffinate from solvent extraction of vacuum distillate from naphthenic oil, which is further broken down into

    1. LNAP – naphthenic plasticisers of medium viscosity;

    2. HNAP – naphthenic plasticisers of high viscosity.

From early 2010, a ban on the use of high aromatic plasticisers [7] was introduced, which challenged the oil and tyre industry to replace the DAE high aromatic plasticisers with other process oils.

Patent application EP 3031621 A1 [17] of The Goodyear Tire & Rubber Company; PNEUMATIC TIRE, describes the production of a pneumatic tyre based on oiled rubber compositions and addition of process oil directly when composing the rubber mixture.

Plasticisers of the type MES, TDAE and naphthenic oils are used in the solutions of the said invention, thus the rubber composition contains low polycyclic aromatic compounds (PAC) plasticisers so they do not show carcinogenic activity.

The MES, TDAE or naphthenic type plasticisers with general qualitative characteristics are shown in Table 1.

Table 1

Physiochemical properties of petroleum plasticisers

Properties MES TDAE Heavy naphthenic (HNAP)
Content of carbon atoms in structures: CA, % 11–17 25–30 11–17
Density at 15°C, g/cm3 0.895–0.925 0.930–0.960 0.920–0.950
Viscosity at 40°C, mm2/s 150–230 370–430 350–720
Viscosity at 100°C, mm2/s 13–17 16–22 17–33
VGC viscosity and density constant 0.825–0.865 0.860–0.890 0.840–0.870
Intercept fractions 1.495–1.510 1.520–1.540 1.500–1.520
Glass transition temperature, T g, °C −60 ± 3 −47 ± 3 −45 ± 3
Aniline point, °C 85–100 — —
Solidification point, °C <0 <30 <0
PAC content (DMSO extr.), %(m/m) <2.9 <2.9 <2.9
Flash point, (to) °C 220 240 240

Petroleum plasticisers are important components of rubber products and have a significant impact on their performance characteristics [18]. The function of mineral softeners involves, among others, modification of the physical properties of rubber, particularly by improving tensile strength, hardness, tear resistance and elasticity at low temperatures [18]. The above-mentioned impact of petroleum plasticisers on the performance characteristics of rubber products at low temperatures and an attempt to improve the structural composition of hydrocarbons was an inspiration to study the dewaxing process of the classic TDAE plasticiser.

As a result of the solutions described in numerous patents [19,20,21,22,23,24,25,26,27,28,29], the product obtained is a process oil containing PAC of ≤3% (m/m), which can be used as a softener or plasticiser for rubbers and their mixtures.

The TDAE petroleum plasticisers offered by many producers are distinguished by a plus pour point, which is a feature that can adversely affect the elasticity of rubber products at low temperatures, and hence, in case of a positive effect of the dewaxing process, a decrease in the pour point of those plasticisers can be expected and their performance at low temperatures can be improved.

2 Experimental

2.1 Materials for testing the solvent dewaxing process

Heavy extracts from a selective solvent refining plant were the raw materials for obtaining TDAE plasticisers by the dewaxing process with furfurol (classic process). The physiochemical properties of heavy extracts are presented in Table 2, and the samples of obtained plasticisers TDAE I–III are given in Table 3.

Table 2

Physiochemical properties of raw materials (heavy extracts)

Raw material Test methods
Properties Extract I Extract II Extract III
Density at 20°C, g/cm3 0.9749 0.9893 0.9916 PN-EN ISO 12185
Kinematic viscosity at 50°C, mm2/s 275.43 739.31 783.53 PN-EN ISO 3104
Flash point, (to), °C 275 279 281 PN-EN ISO 2592
Refractive index n D 20 1.5547 1.5614 1.5648 PN-C-04952:81
Sulphur content, % (m/m) 2.76 3.22 3.35 PN-EN ISO 8754
Pour point, °C +29 +26 +25 PN-ISO 3016
PAC content (DMSO extr.), % (m/m) 13.6 12.8 13.0 IP 346
Content of carbon atoms in structures ASTM D 2140
  Aromatic, C A, % 34.51 35.33 36.85
  Naphthenic, C N, % 11.83 15.04 12.29
  Paraffinic C P, % 53.66 49.63 50.86
PAH content, mg/kg Met. GC/MS
  Benzo(a)pyrene 9.4 7.3 6.8
  Benzo(e)pyrene 26.8 25.8 24.9
  Benzo(a)anthracene 5.3 2.4 2.3
  Chrysene 28.5 27.4 18.7
  Benzo(b,j,k)fluoranthene 24.2 14.7 14.3
  Dibenzo(a,h)anthracene 3.5 2.3 1.8
Total PAHs 97.7 79.9 68.8
Table 3

Physiochemical properties of TDAE plasticisers

Plasticiser Test methods
Properties TDAE I TDAE II TDAE III
Density at 20°C, g/cm3 0.9398 0.9478 0.9541 PN-EN ISO 12185
Kinematic viscosity at 100°C, mm2/s 15.33 22.29 24.47 PN-EN ISO 3104
Flash point, (to), °C 276 271 PN-EN ISO 2592
Refractive index n D 20 1.5223 1.5302 1.5349 PN-C-04952:81
Sulphur content, % (m/m) 2.5356 2.68 3.04 PN-EN ISO 8754
Pour point, °C +33 +30 +28 PN-ISO 3016
PAC content (DMSO extr.), % (m/m) 2.7 1.9 2.4 IP 346
Content of carbon atoms in structures ASTM D 2140
  Aromatic, C A, % 20.3 23.86 25.84
  Naphthenic, C N, % 24.2 19.14 16.49
  Paraffinic C P, % 55.5 56.99 57.67
PAH content, mg/kg Met. GC/MS
  Benzo(a)pyrene 0.8 0.7 0.7
  Benzo(e)pyrene 3.1 0.9 0.9
  Benzo(a)anthracene 0.3 0.3 0.4
  Chrysene 1.3 1.1 1.2
  Benzo(b,j,k)fluoranthene 1.4 1.2 1.4
  Dibenzo(a,h)anthracene 0.4 0.1 0.1
Total PAHs 7.3 4.2 4.7

2.2 Laboratory solvent dewaxing process method

Crystallisation of solid hydrocarbons under laboratory conditions is effected with the aid of the method of gradual cooling of the oil–solvent mixture located in the crystalliser. The crystalliser is placed in a cooling bath equipped with a cooling cycle controller to set up the final crystallisation temperature and appropriate cooling rates in the subsequent stages of the process. A nutch filter is connected to a cryostat, provided with a jacket in which the coolant circulates.

The crystallisation process is effected by the dilution method by adding successive portions of the cooled solvent to the cooled mixture of the raw material and solvent, at appropriate moments of the cooling cycle. The first portion of solvent is introduced into the raw material at a temperature at which the raw material forms a homogeneous liquid phase containing no crystals. However, at the point of injection into the mixture, the temperature of the solvent has to be such as to prevent disturbance of the hydrocarbon crystallisation process in the mixture.

In the crystallisation process, continuous mixing of the crystalliser content is effected by means of an agitator with an anchoring ending, with the mixing speed adapted to the increasing viscosity of the mixture.

After reaching the final crystallisation temperature, the separated solid hydrocarbons, containing the occluded solvent, are filtered out from the oil solution in a vacuum nutch. The oil solution (filtrate) accumulates in the receiver tank. The filtered solid hydrocarbons are washed with a portion of cold solvent. The solid hydrocarbons collected from the nutch and the filtrate are subjected to the solvent regeneration process. The solvent regeneration operation is performed by means of nitrogen stripping distillation.

2.3 Solvent dewaxing processes with various TDAE plasticiser solvents

Samples of TDAE plasticisers were subjected to a solvent dewaxing process with three different types of solvents, MEK–TOL (methyl ethyl ketone/toluene mixture), MEK–MIBK (methyl ethyl ketone/methyl isobutyl ketone mixture) and MEK–MTBE (methyl ethyl ketone/methyl tert-butyl ether). To perform solvent dewaxing processes in a laboratory system, similar technology parameters were adopted as those of industrial plants and described in patents [30,31,32,33].

The technology parameters applied are presented in the tables together with mass balances and properties of the deparaffinates obtained and slacks from dewaxing processes. The initial charge of the vacuum distillate in the dewaxing process was 300 g for all the tests carried out. The crystallisation modifier (VISCOPLEX 9-350) was dosed at 1,000 mg/kg according to the manufacturer’s instructions.

3 Results and discussion

3.1 Dewaxing the TDAE plasticiser with the MEK–TOL solvent

Table 4 presents technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, for four MET-TOL dewaxing processes of TDAE I and TDAE III raw material samples.

Table 4

Technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, in MET-TOL dewaxing processes of TDAE I and TDAE III raw material samples

Dewaxing no. PR 01 PR 02 PR 03 PR 04 PR19
Raw material, sample no. TDAE I TDAE I TDAE I TDAE I TDAE III
Technology parameters of dewaxing processes
  MEK–TOL solvent, weight ratio 40:60 40:60 60:40 70:30 50:50
  Crystallisation/filtration temperature, °C −28 −20 −28 −28 −28
  Total solvent to fraction ratio 11:1 11:1 5.0:1 5.0:1 5.0:1
Mass balance of dewaxing processes, averaged results
  Filtration time, s 35 18 14.5 27 19
  Deparafinate yield, % (m/m) 88.0 91.0 89.0 90.0 89.0
  Slack wax yield, % (m/m) 9.0 7.0 6.0 7.0 8.0
  Losses, % (m/m) 3.0 2.0 5.0 3.0 4.0
Properties of deparaffinate
  Kinematic viscosity at 50°C, mm2/s 152.9 138.4 156.3 153.4 289.3
  Kinematic viscosity at 100°C, mm2/s 16.49 15.68 16.58 16.78 24.17
  Refractive index n D 20 1.5253 1.5245 1.5256 1.5258 1.5330
  Density at 20°C, g/cm3 0.9424 0.9408 0.9411 0.9415 0.9563
  Sulphur content, % (m/m) 2.97 3.10 3.10 3.09 3.11
  PAC content (DMSO extr.), % (m/m) — 2.8 2.8 2.8 2.1
  Content of carbon atoms in structures
    Aromatic, C A, % 21.28 20.99 21.51 21.73 24.09
    Naphthenic, C N, % 20.61 19.87 19.98 19.42 18.41
    Paraffinic C P, % 58.11 59.14 58.51 58.85 57.50
  Pour point, °C −15 −15 −22 −14 −15
Slack wax properties
  Refractive index n D 70 1.4705 1.4702 1.4639 1.4687 1.4722
  Solidification point,°C 55.0 60.0 54.8 55.9 56.2
  Oil content, % (m/m) 50.65 0.73 15.60 24.27 28.2

The basic process parameters for four dewaxing operations of the TDAE I raw material were as follows: the mass ratio of MEK–TOL was in the range from 40:60 to 70:30, the crystallisation temperature was −20 or −28°C, and the total solvent to fraction ratio was from 5.0:1 to 11:1.

In the dewaxing attempts of the TDAE I raw material, the deparafinate yield was large and ranged from 88.0 to 91.0% (m/m) and the slack wax yield was in the range of 6.0–9.0% (m/m).

Compared to the TDAE I raw material, as a result of the dewaxing process in the TDAE deparaffinate, an increase in the carbon content in aromatic structures in deparafinate was observed for all tests, which ranged from 0.69 to 1.43%; the content of carbon atoms in naphthenic structures decreased to 3.59–4.78%; and the content of carbon atoms in paraffin structures increased from 2.61 to 3.64%.

It has to be stressed that in all dewaxing attempts, the pour point in the deparaffinate decreased significantly in the range of −14 to −22°C, compared to the raw material whose pour point was +33°C.

Compared to deparaffinates and raw material in slack waxes, the refractive index markedly decreased and the solidification point increased significantly, which indicates the preservation of the selectivity of the TDAE raffinate dewaxing process.

A graphical illustration of the effect of dewaxing process on the change of the structural composition and pour point of deparaffinates is presented in Figures 2 and 3.

Figure 2 Effects of the dewaxing process with the MEK–TOL solvent on the change of the structural composition of deparaffinates – TDAE I raw material.
Figure 2

Effects of the dewaxing process with the MEK–TOL solvent on the change of the structural composition of deparaffinates – TDAE I raw material.

Figure 3 Effect of the dewaxing process with the MEK–TOL solvent on the change of the deparaffinate pour point – TDAE I raw material.
Figure 3

Effect of the dewaxing process with the MEK–TOL solvent on the change of the deparaffinate pour point – TDAE I raw material.

3.2 Dewaxing the TDAE plasticiser with the MIBK–MEK solvent

Table 5 presents technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, for five MIBK–MEK dewaxing processes of a TDAE II raw material sample and two dewaxing processes of the TDAE III raw material sample.

Table 5

Technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, in MIBK–MEK dewaxing processes of TDAE II and TDAE III raw material samples

Dewaxing no. PR 05 PR 06 PR 07 PR 08 PR 09 PR 10 PR 11
Raw material, sample no. TDAE II TDAE II TDAE II TDAE II TDAE II TDAE III TDAE III
Viscosity modifier — Viscoplex 9–350 — — — — Viscoplex 9–350
Technology parameters of dewaxing processes
  MIBK–MEK solvent, mass ratio 100:0 60: 40 80: 20 60: 40 50: 50 60: 40 40: 60
  Crystallisation/filtration temperature, °C −28 −28 −28 −20 −20 −28 −20
  Total solvent to fraction ratio 5.0: 1 5.0: 1 7: 1 5.7: 1 3.5: 1 5.5: 1 3.5: 1
Mass balance of dewaxing processes, averaged results
  Filtration time, s 112 208 62 87 94 54 72
  Deparafinate yield, % (m/m) 87.0 88.0 86.0 89.0 91.0 91.0 92.0
  Slack wax yield, % (m/m) 10.0 7.0 11.0 9.0 6.0 7.0 5.0
  Losses, % (m/m) 3.0 5.0 3.0 2.0 3.0 2.0 3.0
Properties of deparaffinate
  Kinematic viscosity at 50°C, mm2/s 313.8 258.8 294.7 318.9 297.4 323.4 318.2
  Kinematic viscosity at 100°C, mm2/s 25.24 23.09 24.63 25.67 24.93 27.83 27.48
  Refractive index n D 20 1.5134 1.5338 1.5338 1.5334 1.5336 1.5387 1.5184
  Density at 20°C, g/cm3 0.9525 0.9529 0.9564 0.9564 0.9552 0.9527 0.9526
  Sulphur content, % (m/m) 2.78 2.77 3.16 3.19 3.18 3.3 3.20
  PAC content (DMSO extr.), % (m/m) 2.1 2.1 2.2 2.2 2.2 2.7 2.7
  Content of carbon atoms in structures
    Aromatic, C A, % 25.27 24.98 24.93 24.98 25.18 26.81 26.43
    Naphthenic, C N, % 18.89 18.45 18.79 19.34 18.93 17.43 16.97
    Paraffinic C P, % 55.84 56.57 56.28 55.68 55.89 55.76 56.60
  Pour point, °C −15 −15 −12 −13 −13 −16 −14
Slack wax properties
  Refractive index n D 70 1.4720 1.4811 1.4732 1.4743 1.4759 1.4738 1.4749
  Solidification point, °C 53.0 54.0 52.6 54.7 54.1 52.6 52.1
  Oil content, % (m/m) 38.6 31.8 28.5 41.6 36.2 48.3 51.3

The basic process parameters for dewaxing of the TDAE II raw material were as follows: the mass ratio of MIBK–MEK was in the range from 100:0 to 60:40, the crystallisation temperature was −20 or −28°C and the total solvent to fraction ratio was from 3.5:1 to 7:1. In test 46, a crystallisation modifier was used for the process.

In the dewaxing attempts, the deparafinate yield was large and ranged from 86.0 to 89.0% (m/m) and the slack wax yield was in the range of 7.0–11.0% (m/m).

Compared to the TDAE II raw material, as a result of the dewaxing process in the TDAE deparaffinate, an increase in the carbon content in aromatic structures in deparafinate was observed for all tests, which ranged from 1.07 to 1.41%; the content of carbon atoms in naphthenic structures increased max. to 0.20%, or decreased to the max. 0.69%, and the content of carbon atoms in paraffin structures decreased from 0.47 to 1.39%.

In all dewaxing attempts, the pour point in the deparaffinate decreased significantly to the range −12 to −15°C, compared to the raw material whose pour point was +30°C.

Compared to deparaffinates and raw material in slack waxes, the refractive index markedly decreased and the solidification point increased significantly, which indicates the preservation of the selectivity of the TDAE raffinate dewaxing process.

In two dewaxing attempts of the TDAE III raw material, the deparafinate yield ranged from 91.0 to 92.0% (m/m), and the slack wax yield was in the range of 5.0–7.0% (m/m).

Compared to TDAE III raw material, as a result of the dewaxing process, in the TDAE deparaffin, an increase in the content of carbon atoms in aromatic structures was observed in the range of 0.59–0.97%. Significantly reduced pour point occurred in the deparaffinates, −14 to −16°C, compared to the raw material – TDAE plasticiser. Generally, the dewaxing process of the TDAE II and TDAE III raw materials similarly affects the qualitative properties of the deparaffinates and slack waxes obtained from both raw materials.

A graphic illustration of the effect of the dewaxing process on the change of the structural composition and pour point of deparaffinates, for the TDAE II charge, is presented in Figures 4 and 5.

Figure 4 Effect of the dewaxing process with the MBIK–MEK solvent on the change of the structural composition of deparaffinates – TDAE II raw material.
Figure 4

Effect of the dewaxing process with the MBIK–MEK solvent on the change of the structural composition of deparaffinates – TDAE II raw material.

Figure 5 Effect of the dewaxing process with the MBIK–MEK solvent on the change of the deparaffinate pour point – TDAE II raw material.
Figure 5

Effect of the dewaxing process with the MBIK–MEK solvent on the change of the deparaffinate pour point – TDAE II raw material.

3.3 Dewaxing the TDAE plasticiser with the MEK–MTBE solvent

Table 6 presents technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, for five MEK–MTBE dewaxing processes of a TDAE II raw material sample and two dewaxing processes of the sample of raw material TDAE III.

Table 6

Technology parameters, mass balance and properties of the obtained deparaffinates and slack waxes, in MEK–MTBE dewaxing processes of a TDAE II and TDAE III raw material samples

Dewaxing no. PR 12 PR 13 PR 14 PR 15 PR 16 PR 17 PR 18
Raw material, sample no. TDAE II TDAE II TDAE II TDAE II TDAE II TDAE III TDAE III
Viscosity modifier — Viscoplex 9–350 — — — — —
Technology parameters of dewaxing processes
  MEK–MTBE solvent, weight ratio 60:40 40: 60 70: 30 60: 40 70: 30 60: 40 40: 60
  Crystallisation/filtration temperature, °C −28 −28 −20 −20 −30 −28 −20
  Total solvent to fraction ratio 5.0: 1 5.0: 1 7.0: 1 5.7: 1 7.0: 1 5.5: 1 4.0: 1
Mass balance of dewaxing processes, averaged results
  Filtration time, s 72 41 67 94 89 112 125
  Deparafinate yield, % (m/m) 91.0 92.0 92.0 93.0 88.0 89.0 87.0
  Slack wax yield, % (m/m) 7.0 6.0 5.0 5.0 9.0 8.0 9.0
  Losses, % (m/m) 2.0 2.0 3.0 2.0 9.0 3.0 4.0
Properties of deparaffinate
  Kinematic viscosity at 50°C, mm2/s 295.8 289.7 298.4 293.5 301.5 329.7 332.4
  Kinematic viscosity at 100°C, mm2/s 24.74 24.74 24.68 24.67 25.12 28.04 28.13
  Refractive index n D 20 0.9524 1.5332 1.5333 1.5330 1.5336 0.9527 1.5192
  Density at 20°C, g/cm3 0.9524 0.9528 0.9562 0.9524 0.9565 0.9527 0.9529
  Sulphur content, % (m/m) 2.98 2.94 3.02 2.94 3.21 3.30 3.31
  PAC content (DMSO extr.), % (m/m) 2.1 2.2 2.2 2.1 2.3 2.8 2.8
  Content of carbon atoms in structures
    Aromatic, C A, % 24.67 24.58 24.86 24.87 25.23 26.28 26.34
    Naphthenic, C N, % 18.49 18.34 18.45 17.94 18.74 18.43 18.25
    Paraffinic C P, % 56.84 57.08 56.69 57.19 56.03 55.29 55.41
  Pour point, °C −18 −15 −13 −16 −17 −14 −12
Slack wax properties
  Refractive index n D 70 1.4747 1.4745 1.4712 1.4763 1.4812 1.4835 1.4852
  Solidification point, °C 54.0 53.6 55.1 55.0 52.7 52.1 51.3
  Oil content, % (m/m) 34.7 39.4 36.5 31.8 42.3 61.3 60.5

The basic process parameters were as follows: the mass ratio of MEK–MTBE was in the range from 70:30 to 40:60, the crystallisation temperature was −20 or −30°C and the total solvent to fraction ratio was from 5.0:1 to 7.0:1. In test 54, a crystallisation modifier was used for the process.

In the dewaxing attempts, the deparafinate yield was large and ranged from 88.0 to 93.0% (m/m) and the slack wax yield was in the range of 5.0–9.0% (m/m).

Compared to the TDAE II raw material, as a result of the dewaxing process in the TDAE deparaffinate, an increase in the carbon content in aromatic structures in deparafinate was observed for all tests, which ranged from 0.72 to 1.37%; the content of carbon atoms in naphthenic structures decreased to min. 0.40% to max. 1.2%; and the content of carbon atoms in paraffin structures increased to 0.09% or decreased to the max. 0.96%.

In all dewaxing attempts, the pour point in the deparaffinate decreased significantly to the range −13 to −18°C, compared to the raw material whose pour point was +30°C.

Compared to deparaffinates and raw material in slack waxes, the refractive index markedly decreased and the solidification point increased significantly, which indicates the preservation of the selectivity of the TDAE raffinate dewaxing process.

In two dewaxing attempts of the TDAE III raw material, the deparafinate yield ranged from 87.0 to 89.0% (m/m), and the slack wax yield was in the range of 8.0–9.0% (m/m).

Compared to TDAE III raw material, as a result of the dewaxing process, in the TDAE deparaffin, an increase in the content of carbon atoms in aromatic structures was observed in the range 0.44–0.50%. Significantly reduced pour point occurred in the deparaffinates, −12 to −14 °C, compared to the raw material – TDAE plasticiser. Similarly, as for the MEK–MIBK solvent dewaxing process, the MEK–MTBE dewaxing of TDAE II and TDAE III raw materials affects, with the same trend, the qualitative properties of the obtained deparaffinates and slack waxes from both raw materials.

A graphical illustration of the effect of the dewaxing process on the change of the structural composition and pour point of deparaffinates is presented in Figures 6 and 7.

Figure 6 Effect of the dewaxing process with the MBIK–MEK solvent on the change of the structural composition of deparaffinates – TDAE II raw material.
Figure 6

Effect of the dewaxing process with the MBIK–MEK solvent on the change of the structural composition of deparaffinates – TDAE II raw material.

Figure 7 Effect of the dewaxing process with the MEK–MTBE solvent on the change of the deparaffinate pour point – TDAE II raw material.
Figure 7

Effect of the dewaxing process with the MEK–MTBE solvent on the change of the deparaffinate pour point – TDAE II raw material.

3.4 Application tests on a laboratory scale of the TDAE plasticiser for oiled rubber

In the framework of the study, application tests for modified TDAE plasticiser applied were performed to produce oiled rubber KER 1723 and standard rubber compounds.

Raw material – oiled rubbers for the application test were the modified TDAE plasticiser obtained in the process of selective refining with furfurol and the subsequent dewaxing process with the MEK–TOL solvent, which was identified by code TDAE III/PR 19.

To compare the evaluation of the physiochemical properties of oiled rubber containing modified TDAE plasticiser, with requirements for KER 1723 oiled rubber, two coagulations were carried out with the oil in question marked with symbols: TDAE III/PR19/1 and TDAE III/PR19/2. The obtained oiled rubber sample KER 1723 was subjected to laboratory tests for the evaluation of physiochemical and physicomechanical properties. The results of the tests are listed in Tables 7 and 8.

Table 7

Amount of substance and latex parameters during coagulation

Rubber sample TDAE III/PR19/1 TDAE III/PR19/2
Dry mass of the KER 2712 base latex (%) 25 25
ML of the KER 2712 base latex (MU) 130 130
Dusantox 6PPD stabiliser weight (g) 12 12
TDAE oil weight (g) 344 344
Table 8

Results of physiochemical analysis of the oiled rubber KER 1723 based on TDAEIII/PR19

Rubber sample Requirements for the KER 1723 oiled rubber TDAE III/PR19/1 TDAE III/PR19/2
Rolled ML viscosity (MU) 45–55 48.9 50.1
Rolled ML — −13.5 −12.8
Acids (%) 4.0–6.0 5.09 5.12
Soaps (%) max. 0.4 0.13 0.17
Volatile matter content (%) max. 0.8 0.15 0.19
Ash (%) max. 0.4 0.36 0.24
TDAE oil content (%) 25–29 28.0 27.9
Bonded styrene (%) 22–25 23.3 23.4

Laboratory-scale application tests proved that physiochemical properties of the oiled rubber KER 1723 contained the modified plasticiser TDAE III/PR19 to meet the quality requirements of SYNTOS SA in the scope of physiochemical parameters required for oiled rubber.

Further application tests involve the preparation of a standard rubber compound from the KER 1723/TDAE III/PR19 oiled rubber according to ASTM D 3185, Recipe 1 A. The composition of the rubber mixture is presented in Table 9.

Table 9

Composition of rubber compound based on the oiled rubber KER 1723 contained in TDAE III/PR19

No. Component Unit, phr Mass, g
1. KER 1723 oiled rubber 100.00 600.0
2. Zinc white 3.00 18.0
3. Stearin 1.00 6.0
4. Sulphur 1.75 10.5
5. Soot IRB 50.00 300.0
6. TBBS accelerator – (N-tert-butyl-2-benzothiazolylsulfonamide) 1.00 6.0
Total 156.70 940.5

Rubber compounds based on the KER 1723 oiled rubber were subjected to laboratory tests to evaluate the physiochemical properties and performance characteristics, which are presented in Table 10.

Table 10

Physicomechanical properties of the rubber compound based on the KER 1723/TDAE III/PR19/1 and the KER 1723/TDAE III/PR19/2

Rubber compound sample Rubber compound requirements KER 1723/TDAE III/PR19/1 KER 1723/TDAE III/PR19/2
Mixture ML viscosity (MU) — 53.7 52.8
Maximum vulcanisation curve (dNm) 13.5–16.5 15.19 14.94
Minimum vulcanisation curve (dNm) 1.8–2.7 1.94 1.92
TS1 (min) 2.0–5.0 3.72 3.57
T10 (min) — 4.14 3.96
T25 (min) — 5.33 5.12
T50 (min) 5.0–9.0 6.77 6.63
T90 (min) 12.0–17.0 12.94 13.36
Tensile strength (MPa) Minimum 20 20.7 21.6
Elongation at rapture (%) Minimum 320 409 427
Stress at 300% elongation (MPa) 13–17 14.5 14.4
Hardness (°ShA) 60–66 63.5 63.7
Flexibility, Schob method (%) Minimum 28 40.3 41.6

The analysis of the results of rubber compound application tests of rubber made of the KER 1723 oiled rubber contained the modified TDAE III/PR19 plasticiser showed that physicomechanical properties of the vulcanisates meet the requirements specified by SYNTOS SA for reference rubber mixtures.

4 Conclusion

Studies of the solvent dewaxing process with various mixtures, MEK–TOL, MIBK–MEK and MEK–MTBE were carried out for three different TDAE plasticisers.

It was demonstrated that solvent dewaxing of the TDAE plasticiser with positive pour points, meeting the requirements of the Regulation 1907/2006 EU, maintains good process selectivity and allows for a significant reduction of the plasticiser pour point, thus improving the rheological and low-temperature properties.

In all dewaxing attempts, the pour point in the deparaffinate decreased significantly to the range −12 to −22°C, compared to the positive pour points of the raw materials.

For the solvents studied, the effect of lowering the pour point of the TDAE plasticiser in the solvent dewaxing process was obtained, while maintaining quality parameters meeting the requirements of REACH, which can be considered as obtaining a modified TDAE plasticiser with a minus pour point, which should have a positive effect on improving the rubber performance in low product temperatures, particularly the car tyres.

The results achieved in the solvent dewaxing process with the mixture of MEK–TOL, MIBK–MEK and MEK–MTBE and the TDAE plasticiser used for the raw material cause slight shifts in the structural composition of deparafinate, compared to the raw material and do not significantly improve the desired aromatic structure of TDAE raffinates. However, in the assessment of the structural composition of hydrocarbons presented, it should be noted that the structural composition according to ASTM D 2410 [34] is calculated indirectly and may not fully reflect the actual structural change of hydrocarbons after the dewaxing process.

In the attempts of plasticiser dewaxing studied, no favourable change in the structural composition of hydrocarbons was achieved, in particular when it comes to increasing the content of carbon atoms in aromatic structures, compared to the dewaxing charge. Similarly, the content of carbon atoms in naphthenic structures, for some dewaxing tests, increases slightly, while for other tests it decreases, compared to the raw material. Also, the content of carbon atoms in paraffin structures does not decrease much or increases in comparison to the raw material, while the content of paraffins would be desired to significantly decrease, thus improving mainly the content of the aromatic compounds.

Studies on the use of modified plasticisers to produce oiled rubber and vulcanisate meet the quality requirements for those products with regard to the physical and mechanical properties specified by SYNTOS SA.

The study conducted allowed for the preparation of four patent applications with the Patent Office of the Republic of Poland.

Acknowledgements

The authors would like to thank Synthos S.A. for performing the application tests for the sample of the modified TDAE plasticiser provided. The article was written on the statutory work entitled: Assessment impact of the TDAE plasticizer on the quality requirements of rubber products – supported by the Oil and Gas Institute – National Research Institute commissioned by the Ministry of Science and Higher Education, archive number: DK-4100-/80/17, order number: 0093/TO/17.

  1. Funding information: This work was supported by the Oil and Gas Institute – National Research Institute (INiG – PIB) statutory work no. DK-4100-/80/17.

  2. Author contributions: S.P. – supervision, conceptualization, formal analysis, investigation, writing – original draft; W.K. – conceptualization, formal analysis, writing – review & editing; J.J. – validation, writing – review & editing; A.A. – data curation, visualization, writing – review & editing.

  3. Conflict of interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

  4. Ethical approval: The conducted research is not related to either human or animal use.

  5. Data availability statement: All data generated or analysed during this study are included in this published article.

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Received: 2021-05-25
Revised: 2021-08-02
Accepted: 2021-08-04
Published Online: 2021-09-09

© 2021 Stefan Ptak et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/chem-2021-0081
Keywords for this article
petroleum plasticisers; TDAE plasticisers; solvent dewaxing; polycyclic aromatic hydrocarbons; rubber mixtures
Creative Commons
BY 4.0

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  13. Full spectrum and genetic algorithm-selected spectrum-based chemometric methods for simultaneous determination of azilsartan medoxomil, chlorthalidone, and azilsartan: Development, validation, and application on commercial dosage form
  14. Evaluation of the performance of immunoblot and immunodot techniques used to identify autoantibodies in patients with autoimmune diseases
  15. Computational studies by molecular docking of some antiviral drugs with COVID-19 receptors are an approach to medication for COVID-19
  16. Synthesis of amides and esters containing furan rings under microwave-assisted conditions
  17. Simultaneous removal efficiency of H2S and CO2 by high-gravity rotating packed bed: Experiments and simulation
  18. Design, synthesis, and biological activities of novel thiophene, pyrimidine, pyrazole, pyridine, coumarin and isoxazole: Dydrogesterone derivatives as antitumor agents
  19. Content and composition analysis of polysaccharides from Blaps rynchopetera and its macrophage phagocytic activity
  20. A new series of 2,4-thiazolidinediones endowed with potent aldose reductase inhibitory activity
  21. Assessing encapsulation of curcumin in cocoliposome: In vitro study
  22. Rare norisodinosterol derivatives from Xenia umbellata: Isolation and anti-proliferative activity
  23. Comparative study of antioxidant and anticancer activities and HPTLC quantification of rutin in white radish (Raphanus sativus L.) leaves and root extracts grown in Saudi Arabia
  24. Comparison of adsorption properties of commercial silica and rice husk ash (RHA) silica: A study by NIR spectroscopy
  25. Sodium borohydride (NaBH4) as a high-capacity material for next-generation sodium-ion capacitors
  26. Aroma components of tobacco powder from different producing areas based on gas chromatography ion mobility spectrometry
  27. The effects of salinity on changes in characteristics of soils collected in a saline region of the Mekong Delta, Vietnam
  28. Synthesis, properties, and activity of MoVTeNbO catalysts modified by zirconia-pillared clays in oxidative dehydrogenation of ethane
  29. Synthesis and crystal structure of N,N′-bis(4-chlorophenyl)thiourea N,N-dimethylformamide
  30. Quantitative analysis of volatile compounds of four Chinese traditional liquors by SPME-GC-MS and determination of total phenolic contents and antioxidant activities
  31. A novel separation method of the valuable components for activated clay production wastewater
  32. On ve-degree- and ev-degree-based topological properties of crystallographic structure of cuprite Cu2O
  33. Antihyperglycemic effect and phytochemical investigation of Rubia cordifolia (Indian Madder) leaves extract
  34. Microsphere molecularly imprinted solid-phase extraction for diazepam analysis using itaconic acid as a monomer in propanol
  35. A nitric oxide-releasing prodrug promotes apoptosis in human renal carcinoma cells: Involvement of reactive oxygen species
  36. Machine vision-based driving and feedback scheme for digital microfluidics system
  37. Study on the application of a steam-foam drive profile modification technology for heavy oil reservoir development
  38. Ni–Ru-containing mixed oxide-based composites as precursors for ethanol steam reforming catalysts: Effect of the synthesis methods on the structural and catalytic properties
  39. Preparation of composite soybean straw-based materials by LDHs modifying as a solid sorbent for removal of Pb(ii) from water samples
  40. Synthesis and spectral characterizations of vanadyl(ii) and chromium(iii) mixed ligand complexes containing metformin drug and glycine amino acid
  41. In vitro evaluation of lactic acid bacteria with probiotic activity isolated from local pickled leaf mustard from Wuwei in Anhui as substitutes for chemical synthetic additives
  42. Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)
  43. Phosphorylation of Pit-1 by cyclin-dependent kinase 5 at serine 126 is associated with cell proliferation and poor prognosis in prolactinomas
  44. Molecularly imprinted membrane for transport of urea, creatinine, and vitamin B12 as a hemodialysis candidate membrane
  45. Optimization of Murrayafoline A ethanol extraction process from the roots of Glycosmis stenocarpa, and evaluation of its Tumorigenesis inhibition activity on Hep-G2 cells
  46. Highly sensitive determination of α-lipoic acid in pharmaceuticals on a boron-doped diamond electrode
  47. Synthesis, chemo-informatics, and anticancer evaluation of fluorophenyl-isoxazole derivatives
  48. In vitro and in vivo investigation of polypharmacology of propolis extract as anticancer, antibacterial, anti-inflammatory, and chemical properties
  49. Topological indices of bipolar fuzzy incidence graph
  50. Preparation of Fe3O4@SiO2–ZnO catalyst and its catalytic synthesis of rosin glycol ester
  51. Construction of a new luminescent Cd(ii) compound for the detection of Fe3+ and treatment of Hepatitis B
  52. Investigation of bovine serum albumin aggregation upon exposure to silver(i) and copper(ii) metal ions using Zetasizer
  53. Discoloration of methylene blue at neutral pH by heterogeneous photo-Fenton-like reactions using crystalline and amorphous iron oxides
  54. Optimized extraction of polyphenols from leaves of Rosemary (Rosmarinus officinalis L.) grown in Lam Dong province, Vietnam, and evaluation of their antioxidant capacity
  55. Synthesis of novel thiourea-/urea-benzimidazole derivatives as anticancer agents
  56. Potency and selectivity indices of Myristica fragrans Houtt. mace chloroform extract against non-clinical and clinical human pathogens
  57. Simple modifications of nicotinic, isonicotinic, and 2,6-dichloroisonicotinic acids toward new weapons against plant diseases
  58. Synthesis, optical and structural characterisation of ZnS nanoparticles derived from Zn(ii) dithiocarbamate complexes
  59. Presence of short and cyclic peptides in Acacia and Ziziphus honeys may potentiate their medicinal values
  60. The role of vitamin D deficiency and elevated inflammatory biomarkers as risk factors for the progression of diabetic nephropathy in patients with type 2 diabetes mellitus
  61. Quantitative structure–activity relationship study on prolonged anticonvulsant activity of terpene derivatives in pentylenetetrazole test
  62. GADD45B induced the enhancing of cell viability and proliferation in radiotherapy and increased the radioresistance of HONE1 cells
  63. Cannabis sativa L. chemical compositions as potential plasmodium falciparum dihydrofolate reductase-thymidinesynthase enzyme inhibitors: An in silico study for drug development
  64. Dynamics of λ-cyhalothrin disappearance and expression of selected P450 genes in bees depending on the ambient temperature
  65. Identification of synthetic cannabinoid methyl 2-{[1-(cyclohexylmethyl)-1H-indol-3-yl] formamido}-3-methylbutanoate using modern mass spectrometry and nuclear magnetic resonance techniques
  66. Study on the speciation of arsenic in the genuine medicinal material honeysuckle
  67. Two Cu(ii)-based coordination polymers: Crystal structures and treatment activity on periodontitis
  68. Conversion of furfuryl alcohol to ethyl levulinate in the presence of mesoporous aluminosilicate catalyst
  69. Review Articles
  70. Hsien Wu and his major contributions to the chemical era of immunology
  71. Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs
  72. An overview of persistent organic pollutants along the coastal environment of Kuwait
  73. Mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury
  74. COVID-19 and SARS-CoV-2: Everything we know so far – A comprehensive review
  75. Challenge of diabetes mellitus and researchers’ contributions to its control
  76. Advances in the design and application of transition metal oxide-based supercapacitors
  77. Color and composition of beauty products formulated with lemongrass essential oil: Cosmetics formulation with lemongrass essential oil
  78. The structural chemistry of zinc(ii) and nickel(ii) dithiocarbamate complexes
  79. Bioprospecting for antituberculosis natural products – A review
  80. Recent progress in direct urea fuel cell
  81. Rapid Communications
  82. A comparative morphological study of titanium dioxide surface layer dental implants
  83. Changes in the antioxidative properties of honeys during their fermentation
  84. Erratum
  85. Erratum to “Corrosion study of copper in aqueous sulfuric acid solution in the presence of (2E,5E)-2,5-dibenzylidenecyclopentanone and (2E,5E)-bis[(4-dimethylamino)benzylidene]cyclopentanone: Experimental and theoretical study”
  86. Erratum to “Modified TDAE petroleum plasticiser”
  87. Corrigendum
  88. Corrigendum to “A nitric oxide-releasing prodrug promotes apoptosis in human renal carcinoma cells: Involvement of reactive oxygen species”
  89. Special Issue on 3rd IC3PE 2020
  90. Visible light-responsive photocatalyst of SnO2/rGO prepared using Pometia pinnata leaf extract
  91. Antihyperglycemic activity of Centella asiatica (L.) Urb. leaf ethanol extract SNEDDS in zebrafish (Danio rerio)
  92. Selection of oil extraction process from Chlorella species of microalgae by using multi-criteria decision analysis technique for biodiesel production
  93. Special Issue on the 14th Joint Conference of Chemistry (14JCC)
  94. Synthesis and in vitro cytotoxicity evaluation of isatin-pyrrole derivatives against HepG2 cell line
  95. CO2 gas separation using mixed matrix membranes based on polyethersulfone/MIL-100(Al)
  96. Effect of synthesis and activation methods on the character of CoMo/ultrastable Y-zeolite catalysts
  97. Special Issue on Electrochemical Amplified Sensors
  98. Enhancement of graphene oxide through β-cyclodextrin composite to sensitive analysis of an antidepressant: Sulpiride
  99. Investigation of the spectroelectrochemical behavior of quercetin isolated from Zanthoxylum bungeanum
  100. An electrochemical sensor for high sensitive determination of lysozyme based on the aptamer competition approach
  101. An improved non-enzymatic electrochemical sensor amplified with CuO nanostructures for sensitive determination of uric acid
  102. Special Issue on Applied Biochemistry and Biotechnology 2020
  103. Fast discrimination of avocado oil for different extracted methods using headspace-gas chromatography-ion mobility spectroscopy with PCA based on volatile organic compounds
  104. Effect of alkali bases on the synthesis of ZnO quantum dots
  105. Quality evaluation of Cabernet Sauvignon wines in different vintages by 1H nuclear magnetic resonance-based metabolomics
  106. Special Issue on the Joint Science Congress of Materials and Polymers (ISCMP 2019)
  107. Diatomaceous Earth: Characterization, thermal modification, and application
  108. Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite
  109. Special Issue on the Conference of Energy, Fuels, Environment 2020
  110. Assessment of the mercury contamination of landfilled and recovered foundry waste – a case study
  111. Primary energy consumption in selected EU Countries compared to global trends
  112. Modified TDAE petroleum plasticiser
  113. Use of glycerol waste in lactic acid bacteria metabolism for the production of lactic acid: State of the art in Poland
  114. Topical Issue on Applications of Mathematics in Chemistry
  115. Theoretical study of energy, inertia and nullity of phenylene and anthracene
  116. Banhatti, revan and hyper-indices of silicon carbide Si2C3-III[n,m]
  117. Topical Issue on Agriculture
  118. Occurrence of mycotoxins in selected agricultural and commercial products available in eastern Poland
  119. Special Issue on Ethnobotanical, Phytochemical and Biological Investigation of Medicinal Plants
  120. Acute and repeated dose 60-day oral toxicity assessment of chemically characterized Berberis hispanica Boiss. and Reut in Wistar rats
  121. Phytochemical profile, in vitro antioxidant, and anti-protein denaturation activities of Curcuma longa L. rhizome and leaves
  122. Antiplasmodial potential of Eucalyptus obliqua leaf methanolic extract against Plasmodium vivax: An in vitro study
  123. Prunus padus L. bark as a functional promoting component in functional herbal infusions – cyclooxygenase-2 inhibitory, antioxidant, and antimicrobial effects
  124. Molecular and docking studies of tetramethoxy hydroxyflavone compound from Artemisia absinthium against carcinogens found in cigarette smoke
  125. Special Issue on the Joint Science Congress of Materials and Polymers (ISCMP 2020)
  126. Preparation of cypress (Cupressus sempervirens L.) essential oil loaded poly(lactic acid) nanofibers
  127. Influence of mica mineral on flame retardancy and mechanical properties of intumescent flame retardant polypropylene composites
  128. Production and characterization of thermoplastic elastomer foams based on the styrene–ethylene–butylene–styrene (SEBS) rubber and thermoplastic material
  129. Special Issue on Applied Chemistry in Agriculture and Food Science
  130. Impact of essential oils on the development of pathogens of the Fusarium genus and germination parameters of selected crops
  131. Yield, volume, quality, and reduction of biotic stress influenced by titanium application in oilseed rape, winter wheat, and maize cultivations
  132. Influence of potato variety on polyphenol profile composition and glycoalcaloid contents of potato juice
  133. Carryover effect of direct-fed microbial supplementation and early weaning on the growth performance and carcass characteristics of growing Najdi lambs
  134. Special Issue on Applied Biochemistry and Biotechnology (ABB 2021)
  135. The electrochemical redox mechanism and antioxidant activity of polyphenolic compounds based on inlaid multi-walled carbon nanotubes-modified graphite electrode
  136. Study of an adsorption method for trace mercury based on Bacillus subtilis
  137. Special Issue on The 1st Malaysia International Conference on Nanotechnology & Catalysis (MICNC2021)
  138. Mitigating membrane biofouling in biofuel cell system – A review
  139. Mechanical properties of polymeric biomaterials: Modified ePTFE using gamma irradiation
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