Ecorr Recaim in compounds In the technica brochures for Ecorr RBR and Ecorr RNR a detaied overview is given of different appications in which a rubber recaim can be used. Each virgin compound responds different when a part of the virgin rubber is repaced by rubber recaim. Not ony the physica properties but aso the processing properties, such as vucanisation behaviour, are infuenced. If a recaim is used in a compound, it is possibe and / or necessary to optimise the tota compound recipe. During the years, Rubber Resources has deveoped different techniques to minimise these effects. In this brochure exampes are given of compounds in which the different parts of virgin rubber are repaced by rubber recaim.
www.rubber-resources.com Index Ecorr RNR Recaim Natura Rubber in truck tyre tread compound page Ecorr RNR Recaim Natura Rubber in tyre tread compound page Storage hardening of Ecorr RNR Recaim Natura Rubber page 6 Mutipe recaiming with Ecorr RNR Recaim Natura Rubber page 7 Ecorr RBR70 Recaim Buty Rubber in inner iner compounds page 8 Ecorr RNR Recaim Natura Rubber in truck tyre tread compound Rubber Resources Ecorr RNR can be added on top of an existing compound, with adjustment to the curing system. Aso it can be used as a partia substitute for the natura and / or SBR rubber, with adjustment to rubber hydrocarbon content. It is important to notice that the rubber content of a rubber recaim is about 0% and therefore part of virgin rubber has to be repaced by parts of rubber recaim. In tabe an exampe is given in which a truck tyre tread compound is used as a reference compound. Two types of Recaim Natura Rubber, Ecorr RNR B0 and Ecorr RNR B, are added on top of this compound with adjustment of the curing system. The substitution of virgin rubber with a recaim is done for Ecorr RNR B0. As can be seen from the exampes, it depends on the Ecorr RNR type and the method of addition to a compound. For concentrations up to phr of recaim, no difference in the properties of a truck tyre tread compound due to the compounding methods is observed. For higher concentrations compounding on top resuts in better properties, though the compound price reduction is ower. Reference compound Ecorr RNR B0 on top Ecorr RNR B0 partia Ecorr RNR B on top of reference compound substitute of natura rubber of reference compound NR 00 00 97. 94.8 89.6 84.4 73. 00 Carbon back 0 0 0 0 Low PCA Oi Zinc oxide Stearic Acid IPPD TMQ Par. Wax.... Recaim B0 0 0 0 30 0 0 0 30 0 0 0 30 0 TBBS..4.8.66.73.89.0.4.8.67.7.9 Suphur..4.8.66.73.89.0.4.8.67.7.9 Tabe Recipes for substitution or addition of recaim in an existing compound.
Infuence on physica properties Figure Comparison of tensie strength between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). Up to 0 phr, no difference between types of recaim and way of compounding can be seen. At higher concentrations, adding on top resuts in higher tensie strengths. Figure Comparison of eongation at break between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 Figure recaim for RHC (see tabe ). Here the same is true as for the tensie strength: Up to 0 phr no difference can be seen, above that, adding recaim on top of the compound gives better resuts. Figure Figure 3 Figure 3 Comparison of moduus (300%) between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). Substitution for RHC gives more stabe vaues. Figure 4 Comparison of hardness between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for Figure 4 RHC (see tabe ). When adding B0 or B on top of the recaim it provides comparabe vaues as for the reference compound. Figure Comparison of Abrasion between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). Adding B on top of a compound resuts in the owest increase. Figure 3
www.rubber-resources.com Figure 6 Comparison of tear strength between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). Here, adding on top resuts in the best vaues. Figure 6 Figure 7 Comparison of the compression set between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). As expected adding on top resuts in the owest vaues. Figure 7 Figure 8 Comparison of rebound resiience between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). On top adding of recaim has amost no infuence on the rebound resiience. Figure 8 Figure 9 (After ageing: 4 days at 70 C). Comparison of Tensie Strength (MPa) between addition of Ecorr RNR B0 and B on top of an existing compound and substituting B0 recaim for RHC (see tabe ). Addition of recaim improves ageing behaviour because the tensie strength drops ess than the reference compound. 4 Figure 9
Ecorr RNR Recaim Natura Rubber in tyre tread compound Besides the substitution of SBR rubber by a recaim, aso other changes to the compound recipe are possibe and/ or necessary. For exampe, introduction of recaim generay eads to shorter vucanisation times (decrease in ts and t90 ). In tabe, two possibiities are given to compensate this behaviour. First 0, phr of a SBR 00 BR 0 B0 ISAF N34 Low PCA oi Stearic acid Strukto 40 MS TMQ IPPD Antiux 64 ZnO Virgin Compound 80 0-7 3. +0 phr B0 70 0 0 7 3. +PVI 70 0 0 7 3. -PVI - phr CB -0 phr oi 70 0 0 60 3. Pre-Vucanisation-Inhibitor (PVI) is added. It can be seen that this eads to an increase of ts and t90. On the other hand, by using this PVI, aso the price of the tota TBBS SU-09 PVI..4 -..4 -.. 0...4 - compound is increased. A more efficient way of increasing the vucanisation time is by eaving out extra parts of carbon back and processing oi, for these materias Mooney ML(+4)@00 C 7 7 73 7 are aso present in the recaim. The ast coumn shows the advantages of this method:. More comparabe vucanisation behaviour to the virgin reference compound.. An increase of severa physica properties such as Rheo @ 60 C ML MH ts t0 t90 Moduus (MPa) 68 4 39 7 0 0 4 69 3 6 0 8 40 3 69 6 8 7 7 4 4 8 0 3 tensie strength, abrasion, tear strength. 3. Lower compound price due to further savings on car- bon back and processing oi. It must be noted that these are just two exampes of 00% 00% 300% 400% 00%.7.9 6.9 8.6.7.3. 9.3 3.3. 4.9 9.0.9.0 4.6 8.4.4 compound optimisation. The most efficient method differs for each compound. Tensie strength (MPa) Eongation at break (%) 7.4 77 4.7 46 4.8 46. 480 Tabe In the first coumn the recipe and the properties of a tyre tread compound are given. In the second, the infuence of interchanging 0 Hardness ( Shore A) Density (g/cm3) Din Abrasion (mm3) 7.7 8 74.8 06 74.8 8 7.6 7 parts of the SBR rubber by 0 parts of B0 recaim (ñ 0% rubber) is noted. In the ast two coumns two possibe optimisation steps are given with the effect on the compound properties. Tear Deft [N] // [N] 6 7 60 6 7 6 6 9
www.rubber-resources.com Storage hardening of Ecorr RNR Recaim Natura Rubber The phenomenon of the hardening of natura rubber during storage is we known in the rubber industry. Due to the high proportion of natura rubber in tread recaim, the hardening behaviour of recaim during storage is simiar to that of natura rubber. Figure 0 Increase in Mooney as a function of storage time and temperature (M 0 = 40) The Mooney viscosity of tread recaim increases with time due to physica and chemica processes. The increase is dependent on storage time and temperature (see figure 0). It can be cacuated with the foowing empirica equation: M t = Mooney after t days of storage M 0 = Mooney at the day of production t = storage time in days a = 0.04 for T = 3 C = 0. for T = 0 C M t = M 0 * ( + a * t 0. ) Increases in viscosity are argey reversibe with a sma amount of miing. As shown in figure, the viscosity of the aged recaim decreases sharpy during the first minute of miing; further the decine in viscosity is anaogous to that of fresh recaims. Afterwards, the aged recaim behaves ike fresh recaim, having a much ower Mooney viscosity. Recaim with an increase in Mooney viscosity of approximatey 0 points can be masticated easiy with a % increase in tota mixing energy. The processing behaviour and the product properties of compounds with aged vs. fresh recaim (having the same Mooney viscosity at the day of production) do not differ significanty. Figure Mooney as a function of time on a mi for fresh and aged recaims. 0.00.00.00 3.00 4.00.00 6
Mutipe recaiming with Ecorr RNR Recaim Natura Rubber Mutipe recaiming occurs when scrap rubber containing recaim is itsef recaimed. Recaim as a partia substitute is generay used in concentrations not higher than 0%. In this concentration range ony sight differences in properties are caused by mutipe recaiming (see figure 8). The tensie strength of a compound containing a percentage of recaim can be described as foows: T = T 0 ( - α ) + T ( α - _ α n) + Σ T n α n n- n T = Tensie strength of the compound containing a % recaim T 0 = Tensie strength of the compound without recaim T n = Tensie strength of the recaim after n recaiming steps α = Percentage of recaim in the compound This equation is based on a inear reationship between the compound's recaim content and the tensie strength of the recaim as they reate to the resuting tensie strength of the compound. Figure shows the effect of mutipe recaiming on the tensie strength of a compound containing recaim, both cacuated and measured vaues. The cacuation of the tensie strength of this natura rubber compound containing 0% (= a) recaim being recaimed for the first time (n=) wi yied a tensie strength of. MPa: T = 4.4 MPa ( - 0.) + 7.9 MPa * 0. =. MPa The tensie strength of the same compound containing recyced materia which has undergone up to three recaiming steps is.0 MPa: T = 4.4 MPa ( - 0.) + 7.9 MPa (0. - 0. - 0. 3 ) + 6.6 MPa * 0. + 6.0 MPa * 0. 3 =.0 MPa Figure The infuence of mutipe recaiming on the properties of a compound Figure 7
www.rubber-resources.com Ecorr RBR70 Recaim Buty Rubber in inner iner compounds Introduction 8 Most of the Ecorr buty recaim is utiised by the tyre industry in BIIR- and CIIR-inner iner appications. This part provides information on the infuence of Ecorr RBR70 on the most important properties of BIIR- and CIIR-inner iner compounds. The most important properties of an inner iner incude:. Low air permeabiity: buty- and haobuty rubber are characterised by very ow gas permeabiity. Chorine or bromine is introduced in the ay position to the doube bond in order to increase the reactivity of the buty rubber and to make it co-vucanisabe with NR and SBR.. Good ageing- and fatigue-resistance: as a resut of crack initiation and crack growth, air can penetrate between the pies of the tyre causing py separations. In the case of truck tyres, superior ageing performance is required due to higher running temperature and the need for good retreadabiity. 3. Good cured adhesion to NR: due to the ow air permeabiity of the inner iner compound, the formation of trapped air is possibe. This trapped air can cause bisters between the inner iner and the carcass py, particuary at the end of the curing cyce when pressure in the badder is reduced but vucanisation is not yet compete. During consumer use of the tyre, ayer separations might resut from these bisters. 4. Economic considerations: compound price as we as the possibiity of reducing the inner iner's thickness need to be considered. The advantages of Ecorr RBR70 Recaim Buty Rubber in an inner iner compound: The use of Ecorr RBR70 in bromobuty- and chorobutyinner iner compounds provides severa technica and cost benefits: The compound price can be reduced through the incorporation of buty recaim. Increasing the oad of buty recaim reduces air permeabiity. This aows for a reduction in thickness of the inner iner resuting in additiona cost savings and in a reduction in tyre weight. Fex fatigue resistance is improved. In bromobuty-compounds, ageing resistance and green strength are improved. An increasing concentration of buty recaim improves air venting between badder and inner iner during vucanisation. Compound recipes The foowing data were derived using two different compounds, one bromobuty rubber based, and the other chorobuty rubber based. The two compounds are typica in tyre inner iner appications. Mixing was performed in a. itre Homrich-aboratory mixer.
Mixing step I (batch temperature: 3 o C) tabe3 The bromobuty inner iner compound BIIR X Ecorr RBR70 Carbon back N 660 Koresin resin Strukto 40 MS Paraffinic oi Stearic acid Magite D MBTS Mixing step II (Batch temperature: 90 o C) Zn0 Suphur Compound data Rheometer (0DR; 60 o C) t s t 90 00.0 --- 60.00 4.00 7.0 0 8.00.00 0..0 3.00 0.0 3 0 7 0.0 0..0 3.0 0.0 3 0 7 0.0 0.6.60 3.0 0. 3 0 7 0 0.0 0.7.6 3.30 0. 3 0 7 0.0 0.7.70 3.40 0. 3 00 7 0 30.0 0.7.7 3.0 0.60 7 Mixing step I (batch temperature: 3 o C) tabe4 The chorobuty-inner iner compound CIIR 066 SMR0 Ecorr RBR70 Carbon back N 660 Koresin resin Strukto 40 MS Paraffinic oi Stearic acid Mixing step II (Batch temperature: 90 o C) Zn0 MBTS Suphur Compound data Rheometer (0DR; 60 o C) t s t 90 70.0 30.00 --- 60.00 4.00 7.0 0 8.00.00 3.00.0 0.0 3 0 9 30.0 3.08.4 0. 3 0 7 0 0.0 3.7.8 0.3 4 0.0 3..6 0.4 4 0 0 0.0 3.33.67 0.6 4 30.0 3.4.7 0.7 4 0 30.0 3.0.7 0.8 4 0 30 Bromobuty rubber has a high cure rate and short scorch time. For a better process safety the BIIR-compound contains MgO and MBTS. Both chemicas are added during the first mixing step. The ZnO and suphur shoud be added during the second mixing step. 9
www.rubber-resources.com Infuence of Ecorr RBR70 on the properties of the BIIRand CIIR-compounds Lower air permeabiity: The addition of Ecorr RBR70 resuts in a reduction in air permeabiity. This is one of the most important advantages for inner iner appications. Figure Infuence of Ecorr RBR70 on the eongation at break of a BIIR- and a CIIR- inner iner compound (ASTM D 4). Figure 3 Infuence of Ecorr RBR70 on the permeabiity of a BIIR- and a CIIR- inner iner compound (6 o C). Improved ageing resistance of the BIIR-compound: Ageing resistance is improved by the addition of increasing amounts of Ecorr RBR70, especiay in the case of the BIIR compound. Figure 4 and iustrate the effect on tensie strength and eongation at break after ageing at o C for 7 hours in hot air. Improved fex ife after ageing: Just the same as static properties, aso dynamic properties can be improved by compounding with Ecorr RBR70 (after ageing at 0 C, 68 hours). The charts beow iustrate the effect on the fex fatigue behaviour of BIIR- and CIIR compounds. Figure 6 Infuence of Ecorr RBR70 on the fex fatigue resistance of a BIIR- inner iner compound (De Mattia, ISO 3). Figure 4 Infuence of Ecorr RBR70 on the tensie strenght of a BIIRand a CIIR- inner iner compound after ageing (ASTM D 4). 0 Figure 7 Infuence of Ecorr RBR70 on the fex fatigue resistance of a CIIR- inner iner compound (De Mattia, ISO 3).>>
Improved cured adhesion to NR: The addition of Ecorr RBR70 resuts in stronger adhesion of haobuty compounds to NR compounds in the cured state. This effect is more appied in the case of bromobuty compounds, whose cured adhesion is stronger in comparison to the CIIR compounds. Cost savings: Cost savings are achieved through ower compound costs, and due to the reduction of the inner iner's thickness. The atter can be achieved by adjusting the permeabiity/ thickness ratio. The precise cost saving depends on the current price for materia costs and compounding. Other mechanica properties: For the infuence of Ecorr RBR70 on the tensie strength and eongation at break see figures 0 and ; for the effect on moduus and hardness see figures and 3. Figure 8 Infuence of Ecorr RBR70 on the adhesion of a BIIR- and a CIIR- inner iner compound. Improved green strength of BIIR-compounds: The green strength of BIIR compounds is significanty increased by the addition of up to 0 phr Ecorr RBR70. With oadings higher than 0 phr green strength remains on this high eve. Figure 9 aso iustrates the infuence on the green strength of a CIIR compound. Figure 0 Infuence of Ecorr RBR70 on the tensie strenght of a BIIR- and a CIIR- inner iner compound (ASTM D 4). Figure Infuence of Ecorr RBR70 on the eongation at break of a BIIR- and a CIIR- inner iner compound (ASTM D 4). << Figure 9 Infuence of Ecorr RBR70 on the green strenght of a BIIR- and a CIIR- inner iner compound.
Storage and handing of Buty recaim Figure Infuence of Ecorr RBR70 on the moduus of a BIIR and CIIR- inner iner compound (ASTM D 4). Figure 3 Infuence of Ecorr RBR70 on the hardness of a BIIR and CIIR- inner iner compound ( o Shore A,ASTM D 40).. During storage the temperature shoud be coo (< 3 C, preferaby < C), dry (reative humidity ower than 6%), dust free and moderatey ventiated.. Recaim shoud be protected from ight, in particuar from direct sunight and strong artificia ight with a high utravioet content. 3. Recaim shoud be protected from circuating air by a protective packaging or by storage in airtight containers. Ozone concentration in the storage room shoud be beow 0 ppm. Therefore the storage area shoud not contain any equipment capabe of generating ozone. 4. Recaim shoud be stored under conditions free from compression, tension or other possibe sources of deformation.. Athough the mooney increase for buty recaim is very ow, the recaim inventory shoud be rotated on a 'first in, first out' basis. Infuence on processabiity No significant negative infuence on the processabiity of the compound has been observed. The foowing infuences shoud be mentioned:. Tack is not significanty infuenced.. Die-swe is reduced, but mi shrinkage is increased sighty. Rubber Resources B.V. Schoenerweg 36-6 NX Maastricht - P.O. Box 437-600 AK Maastricht - The Netherands Phone: +3 (0)43 39 04 44 - Fax: +3 (0)43 39 03 03 - E-mai: info@rubber-resources.com - Website: www.rubber-resources.com A rights reserved. No part of this pubication may be reproduced, stored in a retrieva system, or transmitted in any form or by any means without the prior written permission of Rubber Resources. No responsibiity is assumed by Rubber Resources for any injury and / or damage to persons or property as a matter of products iabiity, negigence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the materia herein.