Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 31 Aus Wissenschaft und Forschung 1 Introduction Group I mineral base oil is the workhorse of the industrial lubricants business. Today, 70 % of all Group I base oils are utilized in industrial applications, and 30 % are used in automotive, mainly HDDO and straight grade engine oil applications. The world base oil market is currently undergoing rapid change. Very large projects for the production of Group II and Group III have been completed in recent years in different regions of the world. Some estimates of the base oil market indicate that, by name plate capacity, the world market would be between 6 and 10 million metric tonnes per annum. This base oil glut spills over onto the Group I producers, which in 2015 alone has resulted in the announced closures in Western Europe of ca. 1.5 million metric tonnes, ca 20 % of the total regional base oil production, Table 1. * Prof. Dr. Thomas Norrby Patrik Salomonsson Linda Malm Nynas AB, Nynashamn, Sweden Group I Replacement Fluids - a Hydraulic Fluid Formulation and Compatibility Study T. Norrby, P. Salomonsson, L. Malm* Eingereicht: 4. 12. 2015 Nach Begutachtung angenommen: 17. 3. 2016 Der Weltmarkt für Grundöle ist in Bewegung: Es ist ein struktureller Wandel zu beobachten, dessen Dynamik für die neuere Zeit beachtlich ist. Während Produktionskapazitäten für Grundöle der Gruppe I rasch verschwinden, nehmen die für Gruppe II rasant zu. Die technischen und wirtschaftlichen Hauptursachen hierfür liegen in den technischen Anforderungen an Kfz-Motoröle. Trotzdem benötigen industrielle Schmierstoffe weiterhin die Eigenschaften der Gruppe I, vor allem im Hinblick auf Viskosität und Lösungsvermögen. Die schnell abnehmende Verfügbarkeit von Ölen der Gruppe I stellt die Hersteller industrieller Schmierstoffe vor erhebliche Probleme. Als Ersatz hat Nynas daher eine Reihe neuer Produkte auf der Grundlage naphthenischer Basisöle entwickelt. Sie bilden die Eigenschaften der Gruppe-I-Öle sehr genau nach; untersucht wurden bei den neuen Produkten die Kälteeigenschaften und die Verträglichkeit mit Elastomeren. Außerdem wurden mit den neuen Grundölen Musterrezepturen für Hydraulikflüssigkeiten entwickelt und geprüft. Wir schlagen sie als geeigneten Ersatz für Grundöle der Gruppe I zur Formulierung industrieller Schmierstoffe für viele Anwendungsbereiche vor. Schlüsselwörter Grundöl, Gruppe I, Stockpunkt, Elastomerverträglichkeit, Hydraulikflüssigkeit, Schaum, RPVOT The world base oil landscape is currently going through rapid structural changes. The rate of change is unparalleled in modern times, with Group I base oil production capacity rapidly declining, and Group II capacity rapidly expanding. The main technical and commercial driver for this change is the technical needs of the automotive engine oil applications. Industrial lubricants, however, have a technical need firmly based in the Group I base oils, mainly due to viscosity and solvency needs. Thus, the rapid decline of Group I availability poses a great challenge for industrial lubricants formulators. Based on our Naphthenic base oil technology, Nynas has developed a new range of Group I replacement base oils. The properties of these closely mimic those of Group I base oils, and we have investigated the low temperature performance, and elastomer material compatibility of these. In addition, we developed and tested model hydraulic fluids based on these new oils. Thus, we propose that the new base oils will serve as a suitable substitute for Group I base oils in many industrial lubricant applications. Keywords Base oil, Group I, Pour Point, elastomer compatibility, hydraulic fluid, foam, RPVOT Kurzfassung Abstract T+S_1_17 13.12.16 07: 53 Seite 31 32 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 Thus, rapid changes in the base oil market, driven mainly by the technical demand from high performance automotive engine oil applications, are impacting all lubricant applications. 2.1 Impact on Industrial Lubricants Some of these highly paraffinic base oils make their way into industrial lubricant formulations, so called overblending (or non-technical demand) [1]. However, many important chemical and physical differences exist between these base oil types. The viscosity range covered in Group I is wider, providing much needed high viscosity to industrial gear oils, greases and engine oils, Table 2. The solvency offered by Group II and Group III, with rapidly increasing aniline points, and lower aromatic carbon type content, is far lower than that of Group I base oils. Thus, some negative effect on the blending of industrial lubricants based on Group II or Group III base oils with existing Group I based industrial product can be foreseen, and have indeed been reported from the field. We propose that the resulting “collateral” damage to the industrial lubricants business could be mitigated by Group I replacement fluids, such as these in this study. Aus Wissenschaft und Forschung Table 1: Announced capacity rationalisation, Western Europe, 2015 Company Location Capacity (tpa) Shell Pernis, Netherlands 370000 Total Gonfreville, France 480000 Colas Dunkerque, France 290000 Nynas Hamburg, Germany 165000 Kuwait Rotterdam, 250000* Petroleum Netherlands *= 1Q, 2016 Table 2: Relative base oil yield in different viscosity grades Light Medium Heavy Bright API group Stock neutral neutral neutral Group I 38 % 13 % 33 % 16 % Group II 55 % 25 % 20 % none Group III 80 % 20 % none none Table 3: Key properties of the New Range (NR) 70 to 600 base oils Characteristics, Test method NR 70 NR 100 NR 150 NR 300 NR 500 NR 600 unit ASTM Density 15 °C (60 °F), kg/ dm 3 D 4052 0.873 0.867 0.871 0.886 0.889 0.876 Viscosity 40 °C, mm2/ s (cSt) D 445 14 22 30 60 100 120 Viscosity 100 °C, mm2/ s (cSt) D 445 3.1 4.2 5.0 7.3 10.2 12.6 Viscosity index D 2270 67 88 87 75 78 96 Viscosity 100 °F, SUS D 2161 78 115 155 312 524 628 Viscosity 210 °F, SUS D 2161 37 40 43 51 61 70 Flash point PM, °C D 93 154 188 202 214 226 250 Pour point, °C D 97 -27 -24 -24 -21 -21 -15 Aniline point, °C D 611 90 100 101 103 108 123 Copper strip, 100 °C, 3 hrs D 130 1 1 1 1 1 1 Sulphur, Wt% D 2622 0.02 0.01 0.04 0.05 0.03 0.02 Colour D 1500 <0.5 <0.5 <0.5 0.5 0.5 1.0 Total acid number, mg KOH/ g D 974 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Hydrocarbon Type Analysis D 2140 CA, % 3 2 3 4 3 1 CN, % 42 36 35 36 36 30 CP, % 55 62 62 60 61 69 Appearance at 15 °C (60 °F) D 4176 Clear & Clear & Clear & Clear & Clear & Clear & Bright Bright Bright Bright Bright Bright DMSO extractable IP 346 < 2 < 2 < 2 < 2 < 2 < 2 compounds, Wt% T+S_1_17 13.12.16 07: 53 Seite 32 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 2.2 Experimental work Nynas has created a new range (NR) of products with Kinematic Viscosity (KV), Viscosity Index (VI) and Aniline Point (AP) closely matching those of existing Solvent Neutral Group I base oils. We conducted a low temperature study, where the treat rate response of a Pour Point Depressant (PPD) additive was investigated. Four reference elastomer materials (two NBRs, one H-NBR and one CR) have been investigated with respect to mass and hardness changes upon immersion in the new range base oils, and in reference base oils and hydraulic fluids. We have also concluded a model hydraulic fluid formulation study, based on our new base oil range. These model fluids have then been tested with respect to physical and chemical properties. They have also been compared to commercially available hydraulic fluids in a miscibility study. Particular attention was paid to oxidation stability, elastomer compatibility, and physical properties such as filterability, foaming tendency, air release, and demulsibility. 2.2.1 Experimental work: development of the New Range of Group I replacement fluids Our starting point was a close analysis of the available technical data for Solvent Neutral (SN) Group I base oils currently available across Europe, ranging from SN 70 to SN 600. We initially selected two key parameters, Kinematic Viscosity at 40 °C (KV) and Aniline Point (AP), as maintaining these would facilitate the retention of current formulations based on Group I base oils. The kinematic viscosity (KV) is the basis for lubricant selection and classification, and the aniline point (AP) serves as a good indicator of solvency: any additive combination soluble in a Group I base oil of similar KV and AP would also form stable solutions in the New Range (NR) of Group I replacement fluids. Also, we would expect additive response and relative treat rates to remain essentially unchanged, thereby facilitating any reformulation work encountered. The key properties of the New Range (NR) of fluids are given in Table 3. A second generation of the New Range, called NR ISO VG, was soon added, where more emphasis was put of KV and Viscosity Index (VI), as a response to frequent queries from the market, Table 4. In the NR ISO VG, we also decided to make available the frequently utilized ISO VG grades 32, 46, 68 and 100 cSt (rather than the 70 to 600 SUS in the first NR range), as most industrial lubricant fluids belong to one or more of these ISO VG grades. By offering a ready-made blend, logistic solutions are simplified, and formulation of e. g. 33 Aus Wissenschaft und Forschung Table 4: Key properties of the New Range (NR) ISO VG 32, 46, 68 and 100 base oils Characteristics, Test method NR ISO NR ISO NR ISO NR ISO unit ASTM VG 32 VG 46 VG 68 VG 100 Density 15 °C (60 °F), kg/ dm 3 D 4052 0.866 0.872 0.874 0.875 Viscosity 40 °C, mm 2 / s (cSt) D 445 32 46 68 100 Viscosity 100 °C, mm 2 / s ( cSt) D 445 5.4 6.7 8.8 11.4 Viscosity index D 2270 102 97 102 100 Viscosity 100 °F, SUS D 2161 163 237 353 504 Viscosity 210 °F, SUS D 2161 44 49 56 64 Flash point PM, °C D 93 204 216 222 236 Pour point, °C D 97 -18 -18 -18 -21 Aniline point, °C D 611 107 110 116 122 Copper strip, 100 °C, 3 hrs D 130 1 1 1 1 Sulphur, Wt% D 2622 0.02 0.02 0.02 0.01 Colour D 1500 <0.5 <0.5 <0.5 <0.5 Total acid number, mg KOH/ g D 974 <0.01 <0.01 <0.01 <0.01 Hydrocarbon Type Analysis D 2140 CA, % 2 2 1 1 CN, % 33 33 33 31 CP, % 65 65 66 68 Appearance at 15 °C (60 °F) D 4176 Clear Clear & Clear & Clear & & Bright Bright Bright Bright DMSO extractable IP 346 < 2 < 2 < 2 < 2 compounds, Wt% T+S_1_17 13.12.16 07: 53 Seite 33 34 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 industrial or mobile application hydraulic fluids is significantly facilitated (see 2.2.4) 2.2.2 Experimental work: Pour Point Depressant (PPD) expression We conducted an initial low temperature study, where the treat rate response of a Pour Point Depressant (PPD) additive was investigated in order to better understand the properties of the NR base oils. Specifically, a treat rate comparison study was made in order to elucidate the interplay between the naphthenic base oil components, and the added PPD additive. We prepared two sets of samples, containing one of the six NR base oils (70 to 600), and either 0.50 % or 0.25 % of PPD additive of a widely available global brand. We found that the lower treat rate 0.25 % (half the commonly used 0.50 %) gave almost the same response for the NR fluids as did a treat rate of 0.50 %. This indicated an improved low temperature performance, and suggested a possible cost-out in e. g. hydraulic fluids formulations (see 2.2.4). For the reference SN 150 fluid, the expected stepwise improvement going from neat oil to 0.25 % or 0.50 % was observed. In Figure 1, the result of adding 0.25 % PPD is shown. Aus Wissenschaft und Forschung Table 5: Base oil effect on hardness and mass of NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008). New range base oils 70 to 600, model industrial hydraulic fluid (HM 46), model mobile hydraulic fluid (HV 46), commercial reference industrial hydraulic fluid (M 46), and reference base oil SN 150. Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR 70 80 -4 -5,1 0,1839 7,55 NR 100 80 -3 -4,2 0,1247 5,32 NR 150 80 -4 -5,3 0,1337 5,61 NR 300 80 -4 -4,7 0,1381 5,81 NR 500 80 -3 -3,8 0,1188 5,04 NR 600 80 -3 -3,6 0,0614 2,51 HM 46 80 -3 -3,5 0,1185 4,58 HV 46 80 -4 -4,5 0,1016 4,01 M 46 80 -3 -4,1 0,1401 5,56 SN 150 80 -2 -3,0 0,0954 3,93 Figure1: PPD response in the New Range base oils 2.2.3 Experimental work: Elastomer base oil compatibility Elastomer compatibility is a key property of base oils, and finished lubricants, e. g. hydraulic fluids [2]. Four reference elastomer materials [3]: two NBRs, one H-NBR and one CR, have been investigated with respect to mass and hardness changes upon immersion for 168 h at 100 °C in the new range base oils, and reference base oil [4], and in reference and model (see 2.2.4) hydraulic fluids [5]. The purpose of this test series was to establish that the new range base oils have similar effect on the elastomer materials as the reference base oil, a standard Figure 2 : Hardness change of NBR 28 % AN, NR 70 to 600 T+S_1_17 13.12.16 07: 53 Seite 34 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 Group I Solvent Neutral (SN) 150. We also included four model hydraulic fluids (see 2.2.4) and two commercially available reference hydraulic fluids, procured and used off the shelf. The results for the elastomer compatibility of the new range base oils 70 to 600 (see Table 3), and reference fluids, for test material NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008), are given in Table 5. As one example, the influence on hardness and mass of NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008) for the same fluids are shown graphically for hardness change, Figure 2, and mass change, Figure 3. All results are found in Appendix I. In Figure 2, the direction of change, moderate loss of hardness (moderate softening), is the same for all base oils and fluids, and the magnitude is small, below -5 %. The commonly permissible variance of hardness is +/ - 10 %, e. g. in the Swedish Standard [6], or in DIN [7]. Likewise, for the second new range base oil series in ISO VG viscosity class (see Table 4), the results for the elastomer compatibility for test material on NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008) are given in Table 6. In this test series, two new model hydraulic fluids HM2 46 and HV2 46, based on the new ISO VG base oils, are included. Select results are shown graphically for hardness change, Figure 4, and mass change, Figure 5. All results are found in Appendix II. In Figure 4, the direction of change, moderate loss of hardness (moderate softening), again 35 Aus Wissenschaft und Forschung Table 6: Base oil effect on hardness and mass of NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008). New range ISO VG 32/ 46/ 68/ 100 base oils, model industrial hydraulic fluid (HM2 46), model mobile hydraulic fluid (HV2 46), and commercial reference industrial hydraulic fluid (M 46). Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR ISO VG 32 80 -2,3 -2,9 0,1094 4,54 NR ISO VG 46 80 -2,3 -2,9 0,1011 4,10 NR ISO VG 68 80 -3,1 -3,9 0,0841 3,21 NR ISO VG 100 80 -1,6 -2,0 0,0564 2,18 HM2 46 80 -2,9 -3,7 0,1106 4,37 HV2 46 80 -3,9 -4,8 0,1162 4,72 M 46 80 -2,4 -3,0 0,1002 4,07 Figure 3: Mass change of NBR 28 % AN, NR 70 to 600 Figure 5: Mass change of NBR 28 % AN, ISO VG 32/ 46/ 68/ 100 series Figure 4 : Hardness change of NBR 28 % AN, ISO VG 32/ 46/ 68/ 100 series T+S_1_17 13.12.16 07: 53 Seite 35 36 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 is the same for all base oils and fluids, and the magnitude is small, below -5 %. The corresponding mass changes (Figure 5) are even smaller than those in Figure 3, less than + 5 % for all fluids. 2.2.4 Experimental work: formulation of model hydraulic fluids Hydraulic fluids are a very important lubricant segment, representing ca 10 % of the global market at 4 million metric tonnes per year. Of these, 1 million tonnes are industrial hydraulic fluids, and 3 million tonnes are mobile hydraulic (high VI, “multi grade”) fluids. Thus, we were keen to demonstrate the usefulness of our new base oils in this core application, and have concluded a model hydraulic fluid formulation study. The formulation study covered industrial (VI ca. 95) and mobile (VI ca. 150) hydraulic fluids. The typical formulations are given in Table 7. We utilized a readily available hydraulic fluid additive package, and likewise readily available PPD and VI Improver rheology modifier packages from global commercial suppliers. The treat rate of the additive package follows the recommendation. The PPD treat rate, 50 % lower than what is usually needed in Group I base oils, was determined in the first part of our study (see 2.2.2). The new model hydraulic fluids, and two commercially available reference hydraulic fluids, were analysed with respect to viscometric properties, pour point and flash point. Oxidation stability of our model fluids was determined by RPVOT [8]. A pass level is set to >300 minutes in the Swedish Standard [6]. In general, all properties more or less confirm to the ex-pectations of hydraulic fluids based on our new base oils. Pour points are lower, and flash points for some of the fluids are lower as well. Please see Table 8 for the general properties of the industrial hydraulic fluids, and Table 9 for the general properties of the mobile hydraulic fluids. In Table 8, please note that the Pour Point of both model industrial hydraulic fluids is very low, at -39 °C. For specimen HM2 46, the flash point increases by 24 °C, and the VI is 100. The oxidation stability by RPVOT also improves for the HM2 46. In Table 9, a similar trend of increasing flash point and oxidation stability by RPVOT, with pour points remaining low, is seen as the base oil changes from NR in HV 46, to the ISO VG range in HV2 46. To further probe the physical properties, filterability [9], foaming tendency [10], air release [11], and demulsibility [12] was investigated. These properties are influenced by the base oils, the interplay of the additives, and by the system history as the fluid ages under use, or become contaminated by dirt, dissolved substances, process fluid or other lubricants. Aus Wissenschaft und Forschung Table 7: Formulation of model hydraulic fluids HM46 HV46 HM2 46 HV2 46 Component %NR 100 - 83,15 - - NR 150 65,9 9,75 - - NR 600 33 - - - NR ISO VG 32 - - - 93,4 NR ISO VG 46 - - 98,9 - HF add pack. 0,85 0,85 0,85 0,85 PPD 0,25 0,25 0,25 0,25 VI Improver - 6,0 5,5 Table 9: General Mobile hydraulic fluid properties Characteris- Test HV 46 HV2 46 V 46, tics, unit method ASTM ref. KV @ 40 °C D 445 45,7 44,9 45,7 KV @ 100 °C D 445 8,24 8,09 7,74 VI D 2270 156 155 138 Density D 4052 0,879 0,870 0,872 (g/ ml @ 15 °C) FP COC (°C) D 92 186 222 232 PP (°C) D 97 -48 -48 -42 RPVOT (min) D 2270 330 388 nd* * = not determined Table 8: General Industrial hydraulic fluid properties Characteris- Test HM 46 HM2 46 M 46, tics, unit method ASTM ref. KV @ 40 °C D 445 46,8 46,2 45,8 KV @ 100 °C D 445 6,6 6,75 6,6 VI D 2270 90 99 94 Density D 4052 0,877 0,873 0,879 (g/ ml @ 15 °C) FP COC (°C) D 92 202 226 244 PP (°C) D 97 -39 -39 -24 RPVOT (min) D 2270 374 420 nd* * = not determined T+S_1_17 13.12.16 07: 53 Seite 36 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 However, the initial properties are still well worth determining, as these forms the base line performance, and will provide very useful information for the trained observer. In Table 10, the base line properties of the two hydraulic fluids, HM 46 and HM2 46 are given. For reference, also ISO 111 58, MH [13] limiting values are presented. The resulting data are in all aspects very promising, and well below the threshold limit values of the ISO 111 58 standard. Very fast air release, and fast and complete demulsibility stand out in this respect. For the high VI Mobile hydraulic fluids, HV 46 and HV2 46, the same properties were investigated. In Table 11, the base line properties of the two hydraulic fluids, HM 46 and HM2 46 are given, again also ISO 111 58 limits are given. The resulting data are again very satisfactory, and below the threshold limit values of the ISO 111 58 standard. Very fast air release, and fast and complete demulsibility stand out in a similar way as for the industrial hydraulic fluids. The final part of the physical properties study was a miscibility study, where our new model hydraulic fluids were blended with two similar and representative hydraulic fluids, one Industrial (called M 46) and one Mobile (called V 46). Such a blending study is frequently performed to assess the miscibility of an industrial lubricant, e. g. a hydraulic, turbine or gear fluid, present in an existing (legacy) lubricant reservoir or system. Typically, three different blends with the proportions 90: 10; 50: 50, and 10: 90 respectively, are prepared. A sufficient volume sample is mixed and stirred for one hour, and then left overnight to give it time to develop any reaction product, precipitates etc. The resulting blends are then tested for filterability, foaming tendency, air release, and demulsibility. In case of real life inuse systems, lubricant fluid suppliers sometime encounter filterability issues, intense foaming etc. usually at one of the extremes (90: 10 or 10: 90). 37 Aus Wissenschaft und Forschung Table 10: Physical properties of the Industrial hydraulic fluids Test Unit HM HM2 ISO b 46 46 Filterability I/ II a 97/ 94 98/ 97 80/ 60 Foam I @24 °C ml/ ml 10/ 0 0/ 0 150/ 0 Foam II @ 93 °C ml/ ml 30/ 0 0/ 0 80/ 0 Foam III @24 °C ml/ ml 10/ 0 0/ 0 150/ 0 Air Release min 2,0 3,9 10 Demulsibility min 10 10 30 Oil/ water/ emuls. ml 40/ 40/ 0 40/ 38/ 2 40/ 37/ 3 a = Dry (no added water), Applied Pressure 100 kPa b = ISO 111 58, HM Table 11: Physical properties of the Mobile hydraulic fluids Test Unit HV HV2 ISO b 46 46 Filterability I/ II a 102/ 96/ 94 80/ 60 102 Foam I @24 °C ml/ ml 10/ 0 20/ 0 150/ 0 Foam II @93 °C ml/ ml 20/ 0 20/ 0 80/ 0 Foam III @24 °C ml/ ml 10/ 0 20/ 0 150/ 0 Air Release min 4,3 2.5 10 Demulsibility min 5 10 30 Oil/ water/ emuls. ml 40/ 40/ 0 40/ 40/ 0 40/ 37/ 3 a = Dry (no added water), Applied Pressure 100 kPa b = ISO 111 58, HM Table 12: Miscibility study 1, Industrial hydraulic fluids HM 46 and M 46. The 90: 10 blend thus is composed of 90 % HM46 and 10 % M 46 Test Unit 90: 10 50: 50 10: 90 Filterability I/ II a 98/ 95 96/ 92 99/ 96 Foam I @24 °C ml/ ml 10/ 0 10/ 0 10/ 0 Foam II @93 °C ml/ ml 20/ 0 20/ 0 30/ 0 Foam III @24 °C ml/ ml 20/ 0 30/ 0 30/ 0 Air Release min 2,5 2,8 3,1 Demulsibility min 10 10 15 Oil/ water/ emuls. ml 40/ 40/ 0 40/ 37/ 3 40/ 38/ 2 a = Dry (no added water), Applied Pressure 100 kPa Table 13: Miscibility study 2, Mobile hydraulic fluids HV 46 and V 46. The 90: 10 blend thus is composed of 90 % HV46 and 10 % V 46 Test Unit 90: 10 50: 50 10: 90 Filterability I/ II a 98/ 95 103/ 98 98/ 87 Foam I @24 °C ml/ ml 0/ 0 0/ 0 0/ 0 Foam II @93 °C ml/ ml 20/ 0 30/ 0 30/ 0 Foam III @24 °C ml/ ml 0/ 0 0/ 0 10/ 0 Air Release min 3,6 2,8 2,8 Demulsibility min 5 10 15 Oil/ water/ emuls. ml 40/ 40/ 0 40/ 40/ 0 40/ 38/ 2 a = Dry (no added water), Applied Pressure 100 kPa T+S_1_17 13.12.16 07: 53 Seite 37 38 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 The information thus revealed is commonly utilized as a guideline for the application support team during a transition from one fluid supplier to another. In this case, as we are mixing and analysing fresh, unused hydraulic fluids, we do not expect to find any major incompatibilities or disturbance of properties. The results are given in Table 12 for the Industrial hydraulic fluid blends and in Table 13 for the Mobile hydraulic fluid blends. The same commercially available hydraulics fluids, M 46 and v 46, were utilised also for this part of the study. For ISO 111 58 reference value, please see Table 10 or 11. In Table 12, no detrimental effects can be seen. Air release remains very fast, and only a slight increase of the demulsibility time for 10: 90 stands out, but is still well within the limits of the ISO 111 58. In Table 13, again no detrimental effects can be seen. A slight increase of the demulsibility time for 10: 90 once again is observed, but is still well within the limits of the ISO 111 58. 3 Results and discussion In this study, we outline the design and testing of new range of specialty base oils, with its roots in Nynas’ naphthenic heritage. We set out to formulate one new range series to closely match the Kinematic Viscosity (KV) and Aniline Point (AP) of a reference set of Solvent Neutral Group I base oils, from 70 to 600 (SUS at 100 °F), Table 3. We also developed a second generation of these new base oils, Table 4, with ISO VG grade Kinematic Viscosity, and with Viscosity Index (VI) of 95 or more, as many end users find also the VI to be very helpful. We matched the KV, AP and VI according to our design expectations. The first applied study was in low temperature properties, especially the treat rate response and expression of added Pour Point Depressant (PPD) additive. We could establish a new, lower recommended use treat rate, at 50 % below conventionally used, for the new base oils. We conclude that a combination of lower content of nalkane wax precursor molecules, in combination with a higher content of multi ring naphthenic molecules contribute to the very good low temperature performance. This property was also found to be retained in the fully formulated model industrial and mobile hydraulic fluids that we developed, based on these new base oils. The purpose of the elastomer compatibility study was primarily to confirm out hypothesis that a solvency retained at similar levels as found in Group I base oils, would result in very similar elastomer-fluid interaction, and retained seal material behaviour. Specifically, we wanted to make sure that seal hardness and mass changes were of similar magnitude and in the same direction, as not to present the seal material with any additional challenges to satisfy the design need in a machine construction. We could determine that the elastomer material response to the new base oils met these expectations, and that our screening method was sufficiently sensitive, as seen in the response vs Chloroprene rubber (CR). We conclude that these elastomer experiments would serve as a no-harm screening study, and lends further support to our approach to Group I replacement base oils. For more extensive data, please see Appendix I and II. The model hydraulic fluids, four in all, that were prepared by blending of the new base oils with commercially available industry standard additives displayed the desired and expected properties. Close comparison, and miscibility testing, versus two commercially available hydraulic fluids indicate that the task of formulating and testing hydraulic fluids, based on our new base oils, would be feasible. As expected, the model hydraulic fluids based on the New Range ISO VG base oils display higher VI (for the Industrial hydraulic fluid HM2 46), and higher flash points for both the industrial (HM2 46) and mobile (HV2 46) model hydraulic fluids. The pour points remain low, a possible additional benefit for the end user. 4 Conclusions The results suggest that it is indeed possible to reproduce the key features of Group I base oils, and to formulate hydraulic fluids based on these. The new range of Group I replacement fluids thus offers a convenient way around compatibility, solubility and extensive reformulation issues that industrial lubricant blenders otherwise must conquer when formulating in base oils other than Group I, due to increasingly poor market availability, or by design choice. 5 References [1] Phadke. M., “Synthetic Basestocks Market -Market Trends and Outlook”, Proceedings of The 2015 European Base Oils & Lubricants Summit”, Vienna, September 2015 [2] Bock, W. “Hydraulic Oil”, Chapter 11 in “Lubricants and Lubrication”, 2 nd Ed., Editors: Mang, T., and Dresel, W., Wiley-VCH, Weinheim, Germany, 2007. ISBN 978-3- 527-31497-3 [3] Reference rubber materials from BAM, Berlin, Germany. NBR, 28% Acetonitrile (AN), Peroxide cured (BAM E008); NBR, 28 % AN, Sulfur cured (BAM E009), HNBR-1, 35% AN, Peroxide cured (BAM E020), CR, Chloroprene Rubber (BAM E021) Aus Wissenschaft und Forschung T+S_1_17 13.12.16 07: 53 Seite 38 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 [4] ISO 1817: 2015(E), “Rubber, vulcanized or thermoplastic- Determination of the effect of liquids” [5] ISO 6072: 2011(E), “Rubber - Compatibility between hydraulic fluids and standard elastomeric materials” [6] Swedish Standard 155434: 2015 “Hydraulic fluids- Technical requirements, environmental properties and test methods” [7] DIN 51 524 “Minimum requirement of hydraulic fluids” Part 2 and 3 [8] ASTM D 2272-11 method A, “Standard Test Method for Oxidation Stability of Steam Turbine Oils by Rotating Pressure Vessel” [9] ISO 13357-2: 2005, “Petroleum products - Deter-mination of the filterability of lubricating oils - Part 2: Procedure for dry oils” [10] ASTM D 892-13, “Standard Test Method for Foaming Characteristics of Lubricating Oils” [11] ASTM D 3427-12, “Standard Test Method for Air Release Properties of Hydrocarbon Based Oils” [12] ASTM D 1401-10, “Standard Test Method for Water Separability of Petroleum Oils and Synthetic Fluids” [13] ISO 111 58: 2009 “Lubricants, industrial oils and related products (class L) - Family H (hydraulic sys-tems) - Specifications for categories HH, HL, HM, HV and HG” 39 Aus Wissenschaft und Forschung Appendix I Elastomer compatibility with the New Range (NR) 70 to 600 base oils Table 1: Base oil effect on hardness and mass of NBR, 28 % Acetonitrile (AN), Peroxide cured (BAM E008). New range base oils 70 to 600, model industrial hydraulic fluid (HM 46), model mobile hydraulic fluid (HV 46), commercial reference industrial hydraulic fluid (M 46), and reference base oil SN 150. Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR 70 80 -4 -5,1 0,1839 7,55 NR 100 80 -3 -4,2 0,1247 5,32 NR 150 80 -4 -5,3 0,1337 5,61 NR 300 80 -4 -4,7 0,1381 5,81 NR 500 80 -3 -3,8 0,1188 5,04 NR 600 80 -3 -3,6 0,0614 2,51 HM 46 80 -3 -3,5 0,1185 4,58 HV 46 80 -4 -4,5 0,1016 4,01 M 46 80 -3 -4,1 0,1401 5,56 SN 150 80 -2 -3,0 0,0954 3,93 Table 2: Base oil effect on hardness and mass of NBR, 28% Acetonitrile (AN), Sulphur cured (BAM E009). New range base oils 70 to 600, model industrial hydraulic fluid (HM 46), model mobile hydraulic fluid (HV 46), commercial reference industrial hydraulic fluid (M 46), and reference base oil SN 150. Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR 70 80 -6,7 -8,6 0,1587 6,94 NR 100 80 -4,7 -6,1 0,0992 4,20 NR 150 80 -5,5 -7,1 0,1019 4,34 NR 300 80 -5,4 -7,0 0,1007 4,45 NR 500 80 -4,4 -5,8 0,0853 3,70 NR 600 80 -2,5 -3,3 0,029 1,26 HM 46 80 -5,9 -7,7 0,0768 3,31 HV 46 80 -3,2 -4,1 0,0646 2,83 M 46 80 -5,3 -6,8 0,1 4,43 SN 150 80 -2,7 -3,5 0,0636 2,66 T+S_1_17 13.12.16 07: 53 Seite 39 40 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 Aus Wissenschaft und Forschung Table 3: Base oil effect on hardness and mass of HNBR-1, 35% AN, Peroxide cured (BAM E020). New range base oils 70 to 600, model industrial hydraulic fluid (HM 46), model mobile hydraulic fluid (HV 46), commercial reference industrial hydraulic fluid (M 46), and reference base oil SN 150. Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR 70 80 -2 -3,1 0,1388 6,28 NR 100 80 -2 -3,1 0,0816 3,88 NR 150 80 -3 -4,2 0,0773 3,60 NR 300 80 -2 -2,4 0,0886 3,95 NR 500 80 -2 -3,7 0,0733 3,40 NR 600 80 0 0,4 0,0193 0,87 HM 46 80 -2 -3,2 0,0611 2,70 HV 46 80 0 -0,7 0,0416 1,88 M 46 80 -2 -2,5 0,0813 3,61 SN 150 80 -5 -7,1 0,0421 1,92 Table 4: Base oil effect on hardness and mass of CR, Chloroprene Rubber (BAM E021). New range base oils 70 to 600, model industrial hydraulic fluid (HM 46), model mobile hydraulic fluid (HV 46), commercial reference industrial hydraulic fluid (M 46), and reference base oil SN 150. Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR 70 80 -11 -13,4 0,5003 17,35 NR 100 80 -9 -10,8 0,3464 12,46 NR 150 80 -10 -11,5 0,3836 13,29 NR 300 80 -9 -10,4 0,3832 13,12 NR 500 80 -8 -9,8 0,3416 11,99 NR 600 80 -4 -5,1 0,1824 6,24 HM 46 80 -8 -9,9 0,3176 10,78 HV 46 80 -8 -10,0 0,3589 12,31 M 46 80 -8 -9,0 0,3287 11,34 SN 150 80 -7 -8,4 0,2883 10,31 Appendix II Elastomer compatibility with the New Range (NR) ISO VG 32 to 100 base oils Table 1: Base oil effect on hardness and mass of NBR, 28% Acetonitrile (AN), Peroxide cured (BAM E008). New range ISO VG 32/ 46/ 68/ 100 base oils, model industrial hydraulic fluid (HM2 46), model mobile hydraulic fluid (HV2 46), and commercial reference industrial hydraulic fluid (M 46) Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR ISO VG 32 80 -2,3 -2,9 0,1094 4,54 NR ISO VG 46 80 -2,3 -2,9 0,1011 4,10 NR ISO VG 68 80 -3,1 -3,9 0,0841 3,21 NR ISO VG 100 80 -1,6 -2,0 0,0564 2,18 HM2 46 80 -2,9 -3,7 0,1106 4,37 HV2 46 80 -3,9 -4,8 0,1162 4,72 M 46 80 -2,4 -3,0 0,1002 4,07 T+S_1_17 13.12.16 07: 53 Seite 40 Tribologie + Schmierungstechnik 64. Jahrgang 1/ 2017 41 Aus Wissenschaft und Forschung Table 2: Base oil effect on hardness and mass of NBR, 28 % AN, Sulfur cured (BAM E009). New range ISO VG 32/ 46/ 68/ 100 base oils, model industrial hydraulic fluid (HM2 46), model mobile hydraulic fluid (HV2 46), and commercial reference industrial hydraulic fluid (M 46) Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR ISO VG 32 80 -2,9 -3,8 0,0813 3,16 NR ISO VG 46 80 -3,4 -4,4 0,0716 2,85 NR ISO VG 68 80 -4,6 -5,9 0,0481 1,90 NR ISO VG 100 80 -0,5 -0,6 0,0244 0,92 HM2 46 80 -4,0 -5,2 0,0752 3,03 HV2 46 80 -5,0 -6,5 0,0801 3,29 M 46 80 -1,7 -2,3 0,066 2,73 Table 3: Base oil effect on hardness and mass of HNBR-1, 35% AN, Peroxide cured (BAM E020). New range ISO VG 32/ 46/ 68/ 100 base oils, model industrial hydraulic fluid (HM2 46), model mobile hydraulic fluid (HV2 46), and commercial reference industrial hydraulic fluid (M 46) Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR ISO VG 32 80 0 0,5 0,0572 2,49 NR ISO VG 46 80 1 1,4 0,0585 2,46 NR ISO VG 68 80 2 2,9 0,0366 1,58 NR ISO VG 100 80 1 1,0 0,0132 0,60 HM2 46 80 1 1,4 0,0538 2,48 HV2 46 80 1 1,4 0,064 2,72 M 46 80 1 2,2 0,0454 1,90 Table 4: Base oil effect on hardness and mass of CR, Chloroprene Rubber (BAM E021). New range ISO VG 32/ 46/ 68/ 100 base oils, model industrial hydraulic fluid (HM2 46), model mobile hydraulic fluid (HV2 46), and commercial reference industrial hydraulic fluid (M 46) Fluid tested Hardness (start), Hardness change, Hardness change, Mass change Mass change Shore A Shore A % Δ g % NR ISO VG 32 80 -9 -10,2 0,2976 10,39 NR ISO VG 46 80 -9 -10,2 0,321 10,43 NR ISO VG 68 80 -6 -7,1 0,2501 8,14 NR ISO VG 100 80 -4 -4,6 0,1789 6,00 HM2 46 80 -9 -11,2 0,3124 10,08 HV2 46 80 -9 -10,2 0,306 10,65 M 46 80 -8 -10,0 0,3288 10,48 Anzeige Nutzen Sie auch unseren Internet-Novitäten-Service: www.expertverlag.de mit unserem kompletten Verlagsprogramm, über 800 lieferbare Titel aus Wirtschaft und Technik T+S_1_17 13.12.16 07: 53 Seite 41