The invention relates to the use of base oils as extender oils in elastomer production. In particular, the invention relates to the use of gas-to-liquid (GTL) derived base oils as elastomer extender oils.

As reserves of easily accessible oil become more scarce there has been an increasing trend to look towards other sources of hydrocarbons in order to meet current needs for petrochemical products. It has been known to utilise GTL technology in order to convert natural gas into heavier hydrocarbons, typically via a Fischer

Tropsch synthesis reaction. Natural gas is abundant in a number of locations around the world that are easily accessible and, as a result, it represents a promising starting point for hydrocarbon conversion to desirable petrochemical products.

High viscosity base oils derived from GTL synthesis often show a hazy appearance that is typically due to the presence of a small quantity of microcrystalline wax particles .

WO2013/093072 discloses the use of GTL derived hazy high viscosity base oils as extender oils in elastomer compositions .

Elastomer extender oil compositions are added to natural and synthetic elastomers, including rubbers and thermoplastic elastomers (TPE) for a number of reasons, for example to reduce the mixing temperature required during processing and to prevent the scorching of the rubber polymer when it is being ground, to decrease the viscosity of the rubber to improve the general workability of the rubber compound, to aid in the dispersion of fillers, as well as to modify the physical properties of the rubber compound.

The GTL derived base oils comprising hazy components of WO2013/093072 can be used as extender oil in

production of elastomers without the need to remove the haze components.

There remains a general need in the art to further improve the performance of elastomers upon use of GTL derived hazy high viscosity base oils.

It has now surprisingly been found according to the present invention that the GTL derived high viscosity base oil shows better compatibility with the elastomers To this end the present invention provides an elastomer composition that comprises a GTL derived base oil, which GTL derived base oil has not been subjected to a process for the removal of haze components and wherein the GTL derived base oil comprises at least 80 wt . % of compounds having at least 30 carbon atoms.

An advantage of the present invention is that the elastomer composition according to the present invention has surprisingly a low Mooney viscosity, a low glass transition temperature, a low desorption rate, an excellent abrasion performance.

These properties as above may result in less energy necessary to process an elastomer comprising the GTL derived base oil. Furthermore, above described properties of the elastomer composition according to the invention may lead to a lower-better- Volatile Organic Compounds (VOC) and Fogging effect (FOG) performance of elastomers, which can be even improved with reduced oil content .

Another advantage is that the filler content could be increased, e.g. carbon black content in a compound can be increased which could make the rubber more electrical conductive for special applications where electrical conductivity is preferred.

Additionally the deep temperature properties could be improved, therefore the elastomers/TPEs derived by these process oil could operate at deeper temperatures.

The very good abrasion resistance of the elastomer compound supports the use in applications where a high abrasion resistance of elastomers are preferred.

In another embodiment of the invention, there is provided an elastomer composition comprising at least one elastomer component, and a GTL-derived extender oil, wherein the GTL-derived extender oil has not been treated to remove haze components. Typically the base oil comprises a wax component that is present in the range of from at least 0.001 wt% to at most 5 wt%, typically at most 1 wt%, suitably at most no more than 0.1 wt% based on the total weight of the base oil. Suitably the GTL- derived extender oil comprises a GTL-derived base oil that includes at least some paraffinic wax content - i.e. sufficient microcrystalline wax content to render the appearance of the base oil at least partially opaque (hazy) at room temperature and pressure.

In yet another embodiment of the invention, an elastomer composition is provided comprising:

a) at least one elastomer, elastomer component, or mixtures thereof,

b) an extender oil comprising a GTL-derived base oil that includes a microcrystalline wax content, the extender oil present in the range of from at least 0.1 wt% to at most

50 wt% based on the total weight of the elastomer composition, and optionally at least one component selected from: c) reinforcing agents,

d) cross-linking agents and/or cross-linking auxiliaries, e) inorganic and or organic fillers, and

f) waxes and/or antioxidants.

More conventional additives may be used in

elastomers .

A further aspect of the invention provides for a process for the manufacture of an elastomer composition comprising combining at least one elastomer, elastomer component, or a mixture thereof with an extender oil, the extender oil comprising a GTL-derived base oil that includes a haze-causing paraffinic microcrystalline wax content, the extender oil present in the range of from at least 0.1 wt% to at most 50 wt% based on the total weight of the elastomer composition, suitably at least 5 wt% and at most around 20 wt%, more suitably up to at least 15 wt%. Alternatively, the extender oil may be included at a relative amount of at least 0.2 to at most 100 parts per hundred of rubber (PHR) .

The GTL-derived base oil as used in the invention can be a Fischer-Tropsch synthesis product obtained by well-known processes, for example the so-called Sasol process, the Shell Middle Distillate Process or by the ExxonMobil "AGC-21" process. These and other processes are for example described in more detail in EP-A-776959,

EP-A-668342, US A-4943672, US-A-5059299, WO-A-9934917 and WO-A-9920720.

More preferably the Fischer-Tropsch synthesis product comprises at least 80 wt%, preferably at least 85 wt%, and more preferably at least 87 wt% of compounds having at least 30 carbon atoms. Furthermore the weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms of the Fischer-Tropsch product is at least 0.2, preferably at least 0.4 and more preferably at least 0.55.

Preferably the Fischer-Tropsch product comprises a C ₂₀ + fraction having an ASF-alpha value (Anderson-Schulz- Flory chain growth factor) of at least 0.925, preferably at least 0.935, more preferably at least 0.945, even more preferably at least 0.955.

The initial boiling point of the Fischer-Tropsch product may range up to 400 °C, but is preferably below 200 °C. Preferably any compounds having 4 or less carbon atoms and any compounds having a boiling point in that range are separated from a Fischer-Tropsch synthesis product before the Fischer-Tropsch synthesis product is used in said hydroisomerisation step.

Such a Fischer-Tropsch product can be obtained by any process, which yields a relatively heavy Fischer- Tropsch product. However, not all Fischer-Tropsch processes yield such a heavy product. An example of a suitable Fischer-Tropsch process is described in WO-A- 9934917 and in AU-A-698392. These processes may yield a

Fischer-Tropsch product as described above.

The Fischer-Tropsch product will contain no or very little sulphur and nitrogen containing compounds . This is typical for a product derived from a Fischer-Tropsch reaction, which uses synthesis gas containing almost no impurities. Sulphur and nitrogen levels will generally be below the detection limits, which are currently 5 ppm for sulphur and 1 ppm for nitrogen.

The waxy synthesis product of Fischer Tropsch reaction is typically subjected to a

hydrocracking/hydroisomerisation reaction that is suitably performed in the presence of hydrogen and a catalyst, which catalyst can be chosen from those known to one skilled in the art as being suitable for this reaction. Catalysts for use in the hydroisomerisation typically comprise an acidic functionality and a

hydrogenation/dehydrogenation functionality. Preferred acidic functionality' s are refractory metal oxide carriers . Suitable carrier materials include silica, alumina, silica-alumina, zirconia, titania and mixtures thereof. Preferred carrier materials for inclusion in the catalyst for use in the process of this invention are silica, alumina and silica-alumina. A particularly preferred catalyst comprises platinum supported on a silica-alumina carrier. Preferably the catalyst does not contain a halogen compound, such as for example fluorine, because the use of such catalysts require special operating conditions and involve environmental problems.

Examples of suitable hydrocracking/hydroisomerisation processes and suitable catalysts are described in WO-A- 0014179, EP-A-532118, EP-A-666894 and the earlier referred to EP-A-776959.

Preferred hydrogenation/dehydrogenation

functionality's are Group VIIIB metals, for example cobalt, nickel, palladium and platinum and more

preferably platinum. In case of platinum and palladium the catalyst may comprise the hydrogenation/

dehydrogenation active component in an amount of from

0.005 to 5 parts by weight, preferably from 0.02 to 2 parts by weight, per 100 parts by weight of carrier material. In case nickel or cobalt is used a higher content will be present, optionally nickel is used in combination with copper. A particularly preferred catalyst for use in the hydroconversion stage comprises platinum in an amount in the range of from 0.05 to

2 parts by weight, more preferably from 0.1 to 1 parts by weight, per 100 parts by weight of carrier material. The catalyst may also comprise a binder to enhance the strength of the catalyst. The binder can be non-acidic. Examples are clays and other binders known to one skilled in the art .

In the hydroisomerisation the feed is contacted with hydrogen in the presence of the catalyst at elevated temperature and pressure. The temperatures typically will be in the range of from 175 to 380 °C, preferably higher than 250 °C and more preferably from 300 to

370 °C. The pressure will typically be in the range of from 10 to 250 bar and preferably between 20 and 80 bar. Hydrogen may be supplied at a gas hourly space velocity of from 100 to 10000 Nl/l/hr, preferably from 500 to 5000 Nl/l/hr. The hydrocarbon feed may be provided at a weight hourly space velocity of from 0.1 to 5 kg/l/hr, preferably higher than 0.5 kg/l/hr and more preferably lower than 2 kg/l/hr. The ratio of hydrogen to

hydrocarbon feed may range from 100 to 5000 Nl/kg and is preferably from 250 to 2500 Nl/kg.

The conversion in the hydroisomerisation as defined as the weight percentage of the feed boiling above 370 °C which reacts per pass to a fraction boiling below 370 °C, is at least 20 wt%, preferably at least 25 wt%, but preferably not more than 80 wt%, more preferably not more than 70 wt%. The feed as used above in the definition is the total hydrocarbon feed fed to the hydroisomerisation, thus also any optional recycle step.

One or more distillate separations may be performed on the effluent of the hydroisomerisation reaction to obtain at least one middle distillate fuel fraction and heavier hydrocarbon bottoms referred to as the residue. The residue as obtained in such a distillation is optionally subjected to a further distillation performed at near vacuum conditions. This bottom product or residue preferably boils for at least 95 wt% above

370 °C. The vacuum distillation is suitably performed at a pressure of between at least 0.001 and at most 0.1 bara. The residue is obtained as the bottom product of such a vacuum distillation. The 10 wt% recovery boiling point of the residue is typically between 350 and 550 °C .

The wax content of the residue is low to start with although it is sufficient to impart a hazy appearance to base oils derived from the residue. The wax content of the residue can be measured according to the following procedure. 1 weight part of the to be measured oil fraction is diluted with 4 parts of a (50/50 vol/vol) mixture of methyl ethyl ketone and toluene, which is subsequently cooled to -20 °C in a refrigerator. The mixture is subsequently filtered at -20 °C. The wax is thoroughly washed with cold solvent, removed from the filter, dried and weighed. If reference is made to a wax content as a wt% value is meant the percentage of the total oil which is made up of wax.

According to convention the residue would be processed further using any suitable hydroconversion process, which is intended to further reduce the wax content of the residue. The hydroconversion process would typically include special dewaxing catalysts that comprise a molecular sieve optionally in combination with a metal having a hydrogenation function. A minimal amount of wax is required in order to operate additional solvent dewaxing steps in an optimal manner. Solvent dewaxing is well known to those skilled in the art and involves admixture of one or more solvents and/or wax precipitating agents with the base oil precursor fraction and cooling the mixture to a temperature in the range of from -10 °C to -40 °C, to separate the wax from the oil. The oil containing the wax is usually then filtered so as to produce a fully de-hazed final bright stock oil.

Examples of these and other suitable solvent dewaxing processes are described in Lubricant Base Oil and Wax Processing, Avilino Sequeira, Jr, Marcel Dekker Inc., New York, 1994, Chapter 7.

In general, a FT extra heavy base oil for use in the present invention may be prepared by any suitable

Fischer-Tropsch process. Preferably, however, the FT extra heavy base oil component is a heavy bottom fraction obtained from a Fischer-Tropsch derived wax or waxy raffinate feed by: a) hydrocracking/hydroisomerising a Fischer-Tropsch derived wax, wherein at least 20 wt% of compounds in the Fischer-Tropsch derived feed have at least 30 carbon atoms, b) separating the product of step (a) into one or more distillate fraction (s) and a residual heavy fraction, preferably comprising at least 10 wt% of compounds boiling above 540°C;

(c) subjecting the residual fraction to a catalytic hydroisomerisation or pour point reducing step; and

(d) isolating from the effluent of step (c) , preferably as a residual heavy fraction, the Fischer-Tropsch derived paraffinic heavy base oil component.

Under the present invention GTL base oils (i.e. base oils obtained from a Fischer Tropsch synthesis reaction) that comprise haze causing components - such as wax - do not require extensive further processing via methods such as those described. Instead it has been found that the haze causing components do not contribute substantially to a reduction of performance of base oils in

applications such as for use as elastomer extender oils Haze causing components present within the base oils utilised in the present invention typically comprise a soft microcrystalline wax component that has a congealing point as determined by ASTM D 938 of between 85 and 120 °C and more preferably between 95 and 120 °C and a PEN at

43 °C as determined by IP 376 (determination of needle penetration of petroleum wax) of more than 0.8 mm and preferably more than 1 mm. The wax is further

characterized in that it is predominantly paraffinic in nature and preferably comprises less than 1 wt% aromatic compounds and less than 10 wt% naphthenic compounds, more preferably less than 5 wt% naphthenic compounds. The mol percentage of branched paraffins in the wax is typically above 33 and more preferably above 45 and below 80 mol% as determined by C ¹³ NMR. This method determines an average molecular weight for the wax and subsequently determines the mol percentage of molecules having a methyl branch, the mol percentage of molecules having an ethyl branch, the mol percentage of molecules having a C ₃ branch and the mol percentage having a C ₄₊ branch, under the assumption that each molecule does not have more than one branch. The mol% of branched paraffins is the total of these individual percentages. This method calculated the mol% in the wax of an average molecule having only one branch. In reality paraffin molecules having more than one branch may be present. Thus the content of branched paraffins determined by different method may result in a different value.

Conventional haze-free base oils, including bright stock oils, will usually have a kinematic viscosity at

100°C of above 10 cSt which viscosity may range up to 40 cSt and above. Kinematic viscosity may be determined at 40 and 100°C by standard methods including ASTM D445. The pour point is typically below -5°C and even more usually below -21°C. The viscosity index is suitably above 120 and usually above 130. A haze free base oil can also be determined by its cloud point: as determined by ASTM D2500 of near the pour point and below 0°C, usually below -10°C.

Hazy GTL base oils of the present invention are defined as a Fischer Tropsch derived oil having a carbon chain length of typically greater than C _2Q+ and comprising a wax component of between at least around 0.001wt% and at most around 5 wt%, typically at most no more than around 1 %wt, suitably at most no more than 0.1 wt%. The hazy GTL-derived base oils of the invention are visibly at least partially or completely opaque at ambient temperature. Hence, it will be apparent to the skilled person that the base oils utilised in the present invention comprise sufficient additional heavy components (such as wax) to impart a visible haze to the appearance of the oil. As such, the base oils of the present invention would not be described conventionally as

'clear' or 'bright' . Hazy base oils of the invention will typically be rendered clear and bright upon heating to temperatures in excess of 50°C.

In a specific embodiment of the present invention, the GTL derived base oil is defined as a heavy base oil component comprising carbons of up to around C ₄₀ ,

typically in the range of between at least C ₂ o and at most C ₄₀ , as well as haze causing components. The base oil of the invention typically has a kinematic viscosity at 40°C in excess of at least 80 mm ² /s, preferably in excess of at least 100 mm ² /s, more preferably in excess of at least 150 mm ² /s, even more preferably in excess of at least 165 mm ² /s. The base oil of the invention typically has a kinematic viscosity at 100°C in excess of at least of at least 10 mm ² /s, preferably in excess of at least 15 mm ² /s, more preferably in excess of at least 20 mm ² /s, optionally up to around 35 mm ² /s.

Suitably, the base oil of the invention has a Noack point of less than 2% according to ASTM D5800, preferably less than 1.5%.

Also, the base oil of the invention comprises at least 80 wt.%, preferably at least 85 wt . % ad more preferably at least 87 wt.% of compounds having at least

30 carbon atoms.

The aniline point of the base oil of the invention is preferably above 100 according to ASTM D611, more preferably above 125 and most preferably above 150.

Typically, the viscosity index of the base oil of the invention is between 50 and 200, preferably between

100 and 150.

Hence, the invention provides advantageously for the use of so-called extra-heavy hazy base oils as extender oils for elastomer compositions.

In a further specific embodiment of the invention, a GTL derived hazy heavy base oil suitable for use as a elastomer, synthetic rubber extender oil is characterised by a kinematic viscosity at 40°C of 151 mm ² /s and at 100°C of 19 mm ² /s; a cold pour point of -24°C and a density at

15°C of around 837 kg/m ³ .

An embodiment of the invention provides an elastomer composition comprising:

a) at least one elastomer, elastomer component, or mixtures thereof,

b) an extender oil comprising a GTL-derived base oil that includes a microcrystalline wax content, the extender oil present in the range of from at least 0.1 wt% to at most 50 wt% based on the total weight of the elastomer composition, and optionally at least one component selected from:

c) reinforcing agents,

d) cross-linking agents and/or cross-linking auxiliaries, e) inorganic and / or organic fillers, and

f) waxes and/or antioxidants.

Typically, further conventional additives may be used in Rubbers .

Suitably the elastomer is a rubber, optionally selected from elastomers comprising any of the following, including combinations - i.e. copolymers - thereof:

• Natural rubber (NR)

• Isoprene rubber, polyisoprene (IR)

· Styrene-butadiene-rubber (SBR)

• Butadiene rubber (BR)

• Butylene rubber (IIR)

• Ethylene-propylene diene rubber (EPDM)

• Ethylene-propylene rubber (EPM)

· Nitrile butadiene rubber (NBR)

• Chloroprene rubber (CR)

• Thermoplastic elastomer (TPE)

In examples of the invention in use the elastomer is an ethylene propylene diene monomer (EPDM) rubber.

Preferably, the elastomer according to the present invention is EPDM.

Typically TPEs include styrenic block copolymers, polyolefin blends, elastomeric alloys, thermoplastic polyurethanes , thermoplastic copolyesters and

thermoplastic polyamides.

Other compounding agents used in the rubber

industry, such as tackifiers, vulcanization controlling agents, high loss-providing agents and low loss-providing agents, may also be optionally included in the rubber composition .

Examples of reinforcing agents are carbon black and silica. Examples of cross-linking agents and cross- linking auxiliaries are organic peroxides, sulfur and organic sulfur compounds as cross-linking agents, and thiazole compounds and guanidine compounds as the cross- linking auxiliaries. Examples of inorganic fillers are calcium carbonate, magnesium carbonate, clay, china clay

(kaolin clay) , alumina, aluminium hydroxide, mica and the like. An example of an organic filler is carbon black.

Any suitable waxes and/or antioxidants may be incorporated in order to prevent or reduce degradation.

The Mooney viscosity of the elastomer composition according to the present invention at 100°C, comprising china clay as filler, is according to DIN 53523

preferably less than 35 mm ² /s, more preferably less than 30 mm ² /s and most preferably less than 28 mm ² /s.

The Mooney viscosity of EPDM comprising GTL derived heavy base oil according to the present invention at 100°C and china clay as filler is according to DIN 53523 preferably less than 35 mm ² /s, more preferably less than 30 mm ² /s and most preferably less than 28 mm ² /s.

The Mooney viscosity of the elastomer composition according to the present invention at 100°C, comprising carbon black as filler, is according to DIN 53523 preferably less than 120 mm ² /s, more preferably less than 115 mm ² /s and most preferably less than 112 mm ² /s.

The Mooney viscosity of EPDM comprising GTL derived heavy base oil according to the present invention at 100°C and carbon black as filler is according to DIN 53523 preferably less than 120 mm ² /s, more preferably less than 115 mm /s and most preferably less than 112 mm ² / s .

Suitably, the glass temperature of an elastomer composition according to the present invention and china clay or carbon black as filler is according to DIN EN ISO

11357 part 1 less than -60°C, preferably less than 63°C and more preferably less than -65°C.

Suitably, the glass temperature of EPDM and GTL derived heavy base oil according to the present invention and china clay or carbon black as filler is according to

DIN EN ISO 11357 part 1 less than -60°C, preferably less than 62°C, more preferably less than 63°C and most preferably less than -65°C.

Further, the elastomer composition according to the present invention and china clay as filler has according to DIN ISO 4649 an abrasion resistance of preferably less than 320 mm ³ , more preferably less than 315 mm ³ and most preferably less than 314 mm ³ .

Suitably, EPDM and the GTL derived heavy base oil according to the present invention and china clay as filler has according to DIN ISO 4649 an abrasion

resistance of preferably less than 320 mm ³ , more

preferably less than 315 mm ³ and most preferably less than 314 mm ³ .

Also, the elastomer composition according to the present invention and carbon black as filler has

according to DIN ISO 4649 an abrasion resistance of preferably less than 125 mm ³ , more preferably less than 120 mm ³ and most preferably less than 116 mm ³ .

Suitably, EPDM comprising the GTL derived heavy base oil according to the present invention and carbon black as filler has according to DIN ISO 4649 an abrasion resistance of preferably less than 125 mm ³ , more preferably less than 120 mm and most preferably less than 116 mm ³ .

Also, the mass loss for the elastomer according to the present invention is according to DIN 51006 at 300°C preferably less than 5%, more preferably less than 4.5%, and most preferably less than 4.23% based on the total amount of elastomer composition.

Suitably, the mass loss for EPDM comprising the GTL derived heavy base oil according to the present invention is according to DIN 51006 at 300°C preferably less than

5%, more preferably less than 4.5%, and most preferably less than 4.23% based on the total amount of EPDM composition .

In a specific embodiment of the present invention, the elastomer composition comprising china clay as a filler has preferably a Mooney viscosity at 100°C of less than 28 mm ² /s, a glass transition temperature of less than -62°C, an abrasion resistance of less than 314 mm ³ and a mass loss of less than 4.23% based on the total amount of elastomer composition.

Suitably, EPDM comprising a GTL derived heavy base oil according to the present invention comprising china clay as a filler has preferably a Mooney viscosity at 100°C of less than 28 mm ² /s, a glass transition

temperature of less than -62°C, an abrasion resistance of less than 314 mm ³ and mass loss of less than 4.23% based on the total amount of EPDM composition

In another specific embodiment of the present invention, the elastomer composition comprising carbon black as a filler has preferably a Mooney viscosity at 100°C of less than 112 mm ² /s, a glass transition

temperature of less than -63°C, an abrasion resistance of less than 116 mm and a mass loss of less than 4.23% based on the total amount of elastomer composition.

Suitably, EPDM comprising a GTL derived heavy base oil according to the present invention comprising carbon black as a filler has preferably a Mooney viscosity at

100°C of less than 112 mm ² /s, a glass transition

temperature of less than -63°C, an abrasion resistance of less than 116 mm ³ and mass loss of less than 4.23% based on the total amount of EPDM composition.

The method of making the elastomer composition of the present invention comprises the blending of the components of the elastomer composition, components a) to f), in any order. The conditions used in the preparation of the elastomer and rubber compositions of the present invention are known to those skilled in the art.

A specific embodiment of the present invention provides a process for the manufacture of an elastomer composition comprising combining at least one elastomer, elastomer component, or a mixture thereof with an extender oil, the extender oil comprising a GTL-derived base oil that includes a paraffinic wax content, the extender oil present in the range of from at least 0.1 wt% to at most 50 wt% based on the total weight of the elastomer composition (equivalent to 0.2 to 100 parts per hundred rubber) ; and wherein the base oil includes a microcrystalline wax content of between at least 0.001 wt% and at most 5 wt%.

A specific embodiment of the invention also provides for a process for the manufacture of an elastomer product comprising obtaining an elastomer composition according to the process described above, and forming a product from the elastomer composition. The elastomers of the invention may be formed, moulded, rolled, pressed or cut by conventional methods in order to produce an elastomer containing product . The elastomers produced according to the methods of the invention may be formed into a wide variety of products, as will be appreciated by the skilled person including - but not limited to - tyres, elastomer sheeting, washers, o-rings, construction materials, fabrics, coatings, seals, tubing, electrical insulation, membranes, mechanical products, dampers, and clothing .

The invention will be illustrated with the following non-limiting examples.

Examples

Preparation of GTL-derived hazy heavy base oil (XHBO)

A GTL-derived hazy heavy base oil of the invention (denoted as XHBO) was used in the production of EPDM synthetic rubber compositions as described below. XHBO was obtained using a Fischer-Tropsch process. To this end, The total liquid product (C5-750 °C+ fraction) of the Fischer-Tropsch process, as obtained in Example VII using the catalyst of Example III of WO-A-9934917, was continuously fed to a hydrocracking step (a) . The feed contained about 60 wt% C30+ product. The ratio C60+/C30+ was about 0.55. In the hydrocracking step the fraction was contacted with a hydrocracking catalyst of Example 1 of EP-A-532118. The effluent of step (a) was continuously distilled to give a middle distillate fuel fraction and an atmospheric residue fraction. The atmospheric residue fraction was continuously distilled under vacuum to give a heavy distillates fraction and a residual fraction. 60% of the residual fraction was recycled to step (a) and the remaining part was sent to a catalytic dewaxing step (d) . The conditions in the hydrocracking step (a) were: a fresh feed Weight Hourly Space Velocity (WHSV) of 0.6 kg/l.h, recycle feed WHSV of 0.17 kg/l.h, hydrogen gas rate = 750 Nl/kg, total pressure = 77 bar, and a reactor temperature of 334 °C.

In the dewaxing step, the residual fraction was contacted with a dealuminated silica bound ZSM-12 catalyst as described in Example 1 of WO2004/007647, but in this example the catalyst comprises 0.70% by weight Pt and 30 wt% ZSM-12. The dewaxing conditions were 40 bar hydrogen, WHSV = 0.5 kg/l.h and a temperature of 320°C. The properties of the obtained XHBO are given in Table 1. For comparison with XHBO, the following commercially available process oils were included as Comparative Examples :

- Risella X 430 (X430; obtainable from Shell

International Petroleum Company, York Road, London, UK)

- Catenex T 145 (T145; obtainable from Shell

International Petroleum Company, York Road, London, UK)

- Catenex S 946 (S946; obtainable from Shell

International Petroleum Company, York Road, London, UK)

- Catenex S 579 (S579; obtainable from Shell

International Petroleum Company, York Road, London, UK)

Table 1 - Properties of XHBO used in Examples

Preparation of Ethylene-Propylene Diene rubber (EPDM)

EPDM compositions were prepared comprising the hazy base oil of the invention and the comparative oils. The EPDM formulations were of conventional type and are set out in Table 2. The quantities of the components are given as per hundred rubber (PHR) values which is conventional in the art (see page 2, Part 1.2, Rubber Technology: Compounding and Testing for Performance, R. A. Annicelli, Hanser Verlag, 2001) with the total value of the elastomer (rubber) being the sum total of EPDM rubber components shown. The EPDM elastomers prepared as Examples 1-5 were subjected to a variety of industry standard tests for Mooney Viscosity (see Table 3), Glass transition

temperature (see Table 4), thermogravimetric analysis (see Table 5) and abrasion performance (Table 6) .

Unexpectedly, the EPDM elastomer of the invention performs comparatively with the other elastomers of Examples 1-5 which comprise conventional clear and bright extender oils. In fact in some tests it can be seen that the elastomer of XHBO even outperforms the process oils used in comparable elastomers although these process oils have a lower viscosity and even sometimes lower molecular size than XHBO.

Hence, it can be concluded that contrary to the accepted view, that the bigger molecules such as XHBO and the presence of microcrystalline wax in hazy GTL-derived base oils do not lead to impairment or a reduction in the properties of EPDM elastomers that contain said oils as extenders .

Table 2 - China clay EPDM formulations

PHR = parts per hundred rubber

Carbon black EPDM formulations 20 phr

Carbon black EPDM formulations 50 phr

Supplie Examp Examp1

Example 1* Example 2* Example 4 r e 3* e 5

Formulation Generic Description PHR PHR PHR PHR PHR

Keltan 4450 EPDM Lanxess 100 100 100 100 100

Carbon black Carbon black Orion 80 80 80 80 80

Stearic acid Stearic acid Roth 1 1 1 1 1

ZnO ZnO Roth 5 5 5 5 5

XHBO Process oil Shell 50

Shell Catenex T 145 Process oil Shell 50

Shell Risella X 430 Process oil Shell 50

Shell Catenex S 946 Process oil Shell 50

Shell Catenex S 579 Process oil Shell 50

Sulfur sulfur Roth 1,5 1,5 1,5 1,5 1,5

ZincdibenzyIdithiocarbamat Rhein 1,3 e ZBEC Chemie 1,3 1,3 1,3 1,3

Rhein 0, 5 0, 5

Mercaptobenzothiazole MBT Chemie 0,5 0,5 0,5

Determination of Mooney viscosity

DIN 53523 part 2 to 4 was followed for determining the Mooney viscosity. The Mooney viscosities were measured with a MV 3000 Mooney Viscometer (Supplier Mon Tech Werstoffprufmaschinen GmbH) . The Mooney viscosities of the EPDM formulation of XHBO, X 430, T 145, S 946 and S 579 are shown in Table 3. Mooney units in Table 3 are mentioned as MLl+4, 100°C: ML (large rotor) 1 (preheating of 1 minute) +4 (4 minutes test time), 100°C (test temperature) .

Table 3 - Mooney viscosity Of EPDM formulation

The results in Table 3 show that the Mooney viscosity of the EPDM formulation comprising XHBO is comparable with viscosity of the EPDM formulations comprising X430 and T145 and even lower than the viscosities of the EPDM formulations comprising S946 and S579.

These observations indicate that less energy is necessary to process the EPDM formulation comprising XHBO as its resistance to mechanical treatment like extrusion for instance is lower. Furthermore, in the formulation comprising XHBO, the amount of process oil XHBO may be reduced to get the same Mooney viscosity as with the EPDM formulations comprising S946 and S579. This may lead to a lower-better- Volatile Organic Compounds (VOC) and

Fogging effect (FOG) performance of EPDM formulations with a reduced oil content. In addition, the amount and kind of filler content, like carbon black in a EPDM formulation could be increased. This could be beneficial for some features like e.g. the electrical conductivity performance of the rubber.

Determination of Glass transition temperatures

DIN EN ISO 11357 part 1 was followed for determining the transition temperature by DSC. The transition temperature of the EPDM formulations were measured with a

DSC 820 Mettler Toledo GmbH .

Table 4 Glass transition temperature of EPDM formulations and pure process oils/polymer

The results in Table 4 show that with XHBO and the EPDM comprising XHBO a low glass transition temperature (T _G )was obtained. The T _G of the EPDM comprising XHBO is comparable with the TQ' S of the EPDM' s comprising X430, T145, S946 and S579 and sometimes even lower T _G' s are obtained with XHBO (XHBO in Carbon black 20 phr oil vs S946 in Carbon black 20 phr) .

These observations indicate that the EPDM can be used at more extreme lower temperatures and thus extra challenging applications can be managed with XHBO. Furthermore, in the formulation comprising XHBO, the amount of XHBO may be reduced to reach the same extreme low temperature application. This may lead to a lower-better- Volatile

Organic Compounds (VOC) and Fogging effect (FOG) performance of EPDM formulations with a reduced oil content. In addition, the amount and kind of filler content like for example carbon black in a EPDM formulation could be increased. This could be beneficial for the electrical conductivity performance of the process oil.

Thermogravimetric analysis (TGA) of process oils

For the TGA analysis the samples were heated up to

300°C and then run at that specific temperature.

DIN 51006 was followed for determining the mass loss over time at a certain temperature. The mass loss of the process oils were measured with a Thermowaage TGA/SDTA

851 Mettler Toledo GmbH. The results are shown in Table

Table 5 Mass loss in TGA for EPDM rubber 50phr samples containing different process oils

The results in Table 5 show that XHBO containing Elastomer has a comparable low mass loss (desorption ) as S579 containing Elastomer and a much lower mass loss (desorption) compared to Elastomer containing T145, X430 and S946. These observations indicate that XHBO can show unexpected

significant advantages in desorption performance in

rubber/TPE compounds. A low desorption rate is of advantage in VOC/FOG performance. In combination with the other properties as lower mooney viscosity for example the XHBO content could be reduced and an even better desorption performance could be received by reducing the process oil content .

Mechanical characterization - Abrasion data of EPDM

formulations

DIN ISO 4649 06 was followed for determining the abrasion performance of the EPDM formulations. The abrasion resistance was determined using a rotating cylindrical drum device (Abriebprufmachine Zwick 6103) at ambient

temperatures .

The results are shown in Table 6. Table 6 Abrasion resistance of EPDM formulations

The results in Table 6 show that XHBO has a lower abrasion than X430 can has a comparable abrasion to T145 in the china clay rubber recipe. In EPDM rubber carbon black recipe XHBO has a lower abrasion than T145, S946 and S579 and a

comparable abrasion with X430.

These observations indicate that EPDM formulations comprising XHBO has an excellent abrasion performance under mechanical stress . All references cited herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Although particular embodiments of the invention have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the choice of elastomer or the scope of the appended claims, which follow. It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the claims .