Rubber Carbon Black Sulfron 3001 Mixing temperature Reaction temperature Hysteresis characteristics The mixing of Sulfron 3001 in carbon black compounds is described in this paper. The temperature-time prole of mixing between Sulfron and carbon black plays a critical role in realizing the positive effect of Sulfron on hysteresis characteristics. It has been shown that at a mixing temperature 140 C, there is almost no reaction between carbon black and Sulfron 3001. On the other hand, temperature above 165 C of mixing temperature, processing problems could occur because of side reactions of Sulfron 3001 on rubber. Two mixing sequences are described that provides the best results. It has been found that a temperature between 150165 C is required to get the reaction of Sulfron 3001 and carbon black started. The time plays an important role too. It is demonstrated that time required is about 2-2,5 minutes after Sulfron and carbon blacks are added to the rubber mixes after the desired temperature (150-165 C) is reached.
Mixing Aspects of Sulfron 3001 in Carbon Black Compounds
Einmischen von Sulfron 3001 in rugefllte Mischungen
Kautschuk Ru Sulfron 3001 Mischungstemperatur Reaktionstemperatur Hystereseeigenschaften Das Einmischen von Sulfron 3001 in rugefllte Compounds wird beschrieben. Um einen positiven Effekt von Sulfron auf die Hystereseeigenschaften zu erzielen wird der zeitabhngige Verlauf der Mischungstemperatur genutzt. Es wird gezeigt, dass bei Mischungstemperaturen von 140 C keine Reaktion zwischen Ru und Sulfron 3001 auftritt. Andererseits knnen bei Mischungstemperaturen oberhalb 165 C durch Nebenreaktionen des Sulfron auch Verarbeitungsprobleme auftauchen. Es wurde gefunden , dass im Temperaturbereich von 150-165 C die Reaktion zwischen Ru und Sulfron startet, wobei die Reaktionszeit auch bercksichtigt werden mu. In einer Zeit von 2-2,5 min nach der Einarbeitung von Ru und Sulfron und dem Erreichen der empfohlenen Temperatur wird die gewnschte Wirkung erzielt.
The tire industry is continuously striving to reduce the hysteresis of tire compounds. Lower hysteresis signies lower heat generation translating into better durability and service life of tires. With the fuel price rising and concerns to improve the environment is growing, it is becoming important to reduce the rolling resistance of tire compounds. There are discussions on imparting future legislation regarding tire performance including rolling resistance and fuel economy [1]. A considerable reduction of rolling resistance is achieved in passenger tire section by exploiting green tire technology. In this technology, silica/silane concept is applied especially with modied synthetic rubber. For truck/bus tires, where today natural rubber is prime polymer, the use of silica/silane technology can not be applied. Teijin Aramid accepted this challenge and developed a new material based on Twaron that reduces the compound hysteresis signi1 Composition of Sulfron 3001 in percentage Component Twaron, PPTA Stearyl stearate, Wax Processing aid Chemicals, reacted Amounts, % 40 30 20 10
cantly [2-26]. In this paper the mixing of Sulfron is described with an objective to realize the lowest hysteresis losses.
Experimental Compounds Compounds were cured with CBS and sulphur. Zinc oxide, stearic acid, carbon black, oil, antidegradant were incorporated during the rst stage Banbury mixing. Sulfron 3001, composition provided in Table 1, was also added in the Banbury during the nonproductive stage. It is important that Sulfron 3001 should be added together with the carbon black. If technically it is not possible to add Sulfron together with the carbon black, it should be added as soon as possible just after addition of carbon black. See for more detail on mixing recommendation, section 3. The compound formulation is shown in Table 2.
Mixing Master batches of the rubber formulation were prepared in a standard manner using a Banbury (1,6 L) using rotor speed of 76 rpm. The required amount of Sulfron 3001 was added to the mix on a Banbury allowing sufcient time and torque to disperse Sulfron into the rubber matrix. The curatives were added on a two-roll mill. The mixing sequence is shown in Table 3. In order to achieve a temperature of 155165 C, higher rpm up to 145 rpm might be required. Please note that at 2 minutes the rubber temperature should be > 150 C.
Authors R. N. Datta, N. Huntink, M. van der Made, Arnhem (The Netherlands) Corresponding author: Rabin N. Datta Teijin Aramid BV Westervoortsedijk 73 6827 AV Arnhem, The Netherlands E-mail: Rabin.Datta@Teijinaramid.com
Lower amount of wax, because Sulfron contains Wax
108
KGK Mrz 2009
1 Comparison of Payne effect of silica-silane versus carbon blackSulfron 3001
2 Mixing time-temperature ( Total mixing time: 3 min)
The Payne effect of the compounds were studied by using a RPA 2000 (Alpha technologist, USA) at 100 oC and 0.5 Hz frequency at the dynamic strain amplitudes from a low strain of 0.7 % to a high strain of 100 %.
omy. An appropriate demonstration is shown in Figure 1.
as shown in Figure 3. The Payne effect curves are plotted as shown in Figure 4. 3 Mixing sequence Mixing procedure Elastomers ler + Sulfron 3001 REST Sweep Dump Dump temperature Time, min 0 1 2 4 5 155-160 C
Mixing recommendation Carbon black and Sulfron 3001 are to be mixed together during the non-productive stage of mixing. Addition of Sulfron 3001 with polymer or in the nal stage does not work as shown in earlier publication. Depending on the mixing time, mixing recommendation is shown in Figures 2 and 3. It is clear that Sulfron 3001 and carbon black are to be added as early as possible in the Banbury after the mastication stage of the polymer. The temperature should be raised to 150 C by adjusting the rotor speed followed by the addition of rest of the ingredients (except curatives). The temperature (real) should be kept between 150-165 C, and the mixing to be continued for atleast 2-2,5 minutes. A high starting temperature of the mixer (e.g. 90 C) can also be chosen. The compounds (Table II) are mixed for 5 minutes according to the time-temperature protocol
Hysteresis measurement Viscoelastic properties were determined using a Gabo dynamic tester. Test conditions were 10 Hz and 60 C with a dynamic strain of 2 % .
Results and discussion Payne effect
Sulfron 3001 is a chemically modied Twaron matrix designed to react with ller, like carbon black. When added together with carbon black, it signicantly decreases llerller interaction (Payne effect), reducing the frictional energy translated into lower hysteresis signifying reduction in rolling resistance and hence improving the fuel econ-
4 Hysteresis data. GABO const strain 60/10/2 Compound Temperature Frequency Strain Storage E Loss E Tan Complex E* [MPa] [C] [Hz] [%] [MPa] [MPa] CM / test piece / 1.5 t90 min. / 170 C 1 60 10 2 5,001 0,7190 0,1438 5,052 2 60 10 2 4,603 0,5074 0,1102 4,631
KGK Mrz 2009
109
PRFEN UND MESSEN
TESTING AND MEASURING
4 Payne effect of mixes 1 and 2
The Payne effect data are shown in Table 7. It is clear from the Payne effect data that Sulfron 3001 only works when added together with Carbon black. The effect is negligible when Sulfron 3001 is added in the rst stage together with polymer or at later stage together with curatives.
Applications As Sulfron 3001 interacts with carbon black, the material is useful in all carbon black containing compounds. The application is not limited to tread but also could be used in body compounds, such as undertread, belt skim, carcass etc. It is important to indicate that the ller-ller interaction is reduced by applying Sulfron 3001. This is similar to silica/silane compounds where addition of silane reduces the silica-silica interaction (Payne effect).
The hystersis data are summarized in Table 4. It is clear from the data shown in Table 4 that Sulfron 3001 reduces the hysteresis signicantly even with 1,25 phr of Sulfron 3001. Please note that E is also reduced reecting the lower Payne effect.
Effect of mixing time and temperatures
The mixing time after carbon black + Sulfron 3001 is added plays an important role. As shown in the Table 6, the hysteresis data decreases signicantly when the dump temperature is > 150 C < 165 C and the mixing time after Sulfron and carbon black is added is at least 2,5 minutes. The effect of time of 1,5 minutes on tangent delta is less even if we increase the temperature to 160 C.
Tread compounds Tread compounds containing N-100 series or N-200 series, the application of Sulfron 3001 reduces the compound hysteresis by 15-20 %. This will be well reected in the measurement where carbon-carbon interaction (Payne effect) is measured. Hysteresis (tangent delta) measured at 60-70 C at 10-15 Hz with 1-2 % DSA shows a decrease of 15-20 %. More studies are now carried out to nail down the effect of time/temperature of mixing.
Effect of mixing temperature
Mixing at lower temperature (< 140 C) or mixing at > 165 C is not appropriate when Sulfron advantage is looked for. Below 140 C (e.g. 120 C), no or minimum reaction is expected to occur between carbon black and Sulfron 3001. At 165 C, the processing problem pops up because of crosslinking involving side reactions. The mixing time and temperature effect is shown in Table 5. The relative hysteresis data shows that the mixing is optimum when the temperature of mixing is between 150 -165 C. 5 Effect of maximum temperature during mixing CONTROL Dump. Temperature, C Hysteresis 150 100
Sequence of Sulfron 3001 addition
It is described earlier, the Sulfron 3001 only works if added together with carbon blacks. In order to analyse the effect, when Sulfron is added together with polymer or curatives at the nal stage, several mixes were made with (1,5 phr Sulfron 3001) and without Sulfron 3001.
Undertread or belt compounds
Generally undertread compounds or belt skim compounds are reinforced with N-300 series of black. With N-326 black, the effect of Sulfron 3001 (2 phr) shows a reduction of tangent delta with more than 30 %. This is a remarkable achievement based on tire compounds requirements.
Sulfron 3001 150-165 70
Sulfron 3001 120 95
Sulfron 3001 >165 Crosslinking
Guidelines Please follow the mixing time-temperature prole Add Sulfron 3001 together with carbon black or as early as possible after addition of carbon blacks. Avoid using peptizers because it can disturb the reaction. Sulfron 3001 reduces compound viscosity and so elimination of peptizer can bring positive results in properties. In Silica compounds, please add Sulfron 3001 after silica/silane reaction is completed. In mixed ller package, please add Sulfron 3001 after silica/silane reaction is completed. Fill factor of 70 % is advised (can be optimized based on viscosity).
6 Mixing time and temperature effect
Mixing trial Mixing time Sulfron [min.] Dump temperature [C] Tan Improvement [%] A 0 150 0,128 Control B 3,5 150 0,098 25 C 2,5 150 0,105 20 D 1,5 150 0,117 10 E 1,5 155 0,109 15 F 1,5 160 0,109 15
A= Control and B, C, D, E and F are with 1,5 phr of Sulfron 3001
7 Payne effect Mixes Sulfron addition Payne effect Control No Sulfron 200 1 3 Added together with carbon black 95 4 Added together with rubber 175 5 Added together with curatives 180
110
KGK Mrz 2009
Conclusions As described, Sulfron 3001 reacts with carbon black, it is vital therefore that the mixing is properly done. As a recommendation, the following should be taken care: Sulfron 3001 should be mixed in Banbury mixers together with carbon black Sulfron 3001 does not work when mixed together with the polymer Sulfron 3001 does not work when mixed with the curatives The mixing time and temperature is critical. Time plays a more important role than temperature. It is suggested that a mixing time of at least 2,5 minutes is required to obtain the required properties. The dump temperature (real rubber temperature) should lie between 150-165 C (maximum). [3] R. N. Datta, Rubber Chemistry and Technology, 79 2006 26. [4] R. N. Datta and P. J. de Lange, WO. 087161 A 1,2408-2006 (2006). [5] R. N. Datta, Gummi Fasern and Kunstoffe 59 (2006) 754. [6] R. N. Datta and B. Pierik, Kautsch. Gummi Kunstst. 60 (2007) 328. [7] R. N. Datta, Rubber Chem. Technol. 80 (2007) 296. [8] R. N. Datta, N. Huntink, M. van der Made and B. Pierik, Kautschuk Gummi Kunstoffe, 2008, In Press. [9] R. N. Datta, S. Parker, M. van der Made, B. Pierik and N. Huntink, Rubber World, September (2008) 29. [10] R. N. Datta, N. M. Huntink, B. Pierik, Pieter de Lange, Rubber and Plastics news, July 14, 2008. [11] R. N. Datta and N. Huntink , Tire Tech., Koln, 19 th21st February, 2008. [12] R. N. Datta, N. M. Huntink and Sarah Parker, ACS Rubber Division, 2008. [13] B. Pierik and R. Datta, Research Disclosure 524014, December 2007. [14] R. N. Datta, Gummi Fasern Kunststoffe, 59 (2006) 754. [15] R. N. Datta and M. Peters, Rubber World, November (2003) 30. [16] R. N. Datta, Greater tire resistance to cut, chunk, and chip, Tire Technology International (2006) 131. [17] R. N. Datta, Mechanistic study on the role of sulfurized para-aramid short bers in rubber to brass adhesion, ACS, November 1-3, 2005, Pittsburg, USA. [18] R. N. Datta, M. G. M. Peters, S. C. J. Pierik, P. G. Akker, WO 2007/042229 A 1, Teijin Twaron (2007). [19] R. N. Datta and N. Huntink, Tire Technology, February 19-22, 2007, Koln, Germany. [20] R. N. Datta and C. Leutewiller, Brazilian Rubber Conference, May 6-8, 2007, Sao Paolo, Brazil. [21] R. N. Datta and N. Huntink, ACS Rubber Division, 2006, Cleveland, Ohio, USA. [22] R. N. Datta, A futuristic material for improving tire performance, paper no 8 B, India International Rubber Conference, 1-3rd November 2007, Udaipur, India. [23] R. N. Datta, N. Huntink, Bas Pierik and Sarah Parker, ITEC, Paper 14 B, Akron, 2008. [24] R. N. Datta, Rubber, Fibers and Plastics 2 (2007) 154. [25] R. N. Datta and N. M. Huntink, Rubber, Fibers and Plastics 3 (2008) 146. [26] R. N. Datta and N. M. Huntink, Gummi Fasern Kunstoffe 60 (2007) 708.
References [1] EU draft regulation on Tire performance, Commission of the European Communities, Brussels 23.05.2008, SEC (2008) 1908. [2] R. N. Datta, Improved Hysteresis in Truck Tread Compounds by Using Aramid Short Fibers, 165 th Spring Rubber Division, ACS Meeting, Proceed. Grand Rapids, May 17-19,2004.
