Naphthenic process oils

Naphthenic process oil is used in high volume in general-purpose rubber compounds. Naphthenic oils are usually derived from naphthenic crudes that are more limited in supply than paraffinic crudes. In the world only about 5% of all crude is naphthenic crude. Only certain regions have naphthenic crudes. Pennsylvania was one of these regions, but today much of the naphthenic crudes come from Venezuela. 

Naphthenic process oil costs more to produce than aromatic oil because more value is added from a more complex production process as shown in Eigure 9.2. 

Many times the extent of hydrotreatment will determine if the oil product will require a cancer warning label. If the oil did not receive sufficient hydrotreating, a cancer warning label (according to the US OSUA Hazard Communication Standard) is required. 

ASTM D2226 classifies petroleum process oils used in rubber compounding. This system of classification is based on the test results from ASTM D2007, a column chromatographic method called clay-gel analysis. This procedure classifies oil based on its content of saturated, aromatic, and polar compounds, as well as asphaltene content. Under this classification system, naphthenic oil is designated Type 103. 

Golden Bear Oil Specialties R.E. Carroll E.C. Morris Nynas USA 

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Calsol. [Calumet] Naphthenic process oil for rubber indus, resin extending, PVC, textiles, caulldng compds. 

Oil that serves as a temporary or permanent component of a manufactured product. Aromatic process oils have good solvency characteristics their applications include proprietary chemical formulations, ink oils, and extenders in synthetic rubbers. Naphthenic process oils are characterized by low pour points and good solvency properties their applications include rubber compounding, printing inks, textile conditioning, leather tanning. 

Many compounders believe that naphthenic process oil is the best choice for natural rubber-based compounds. Naphthenic process oil is used in very large quantities in compounds based on general-purpose elastomers. With the decreasing future use of... 

Rosin oil is essentially an economical alternative to using more expensive phenolic tackiflers with aromatic or naphthenic processing oil. During the 1980s and 1990s there was a period of declining use. However, with improvements in the quality... 

Total aromatics (by clay-gel analysis) of 30% minimum are the general boundary although not hard and fast. Generally, naphthenic process oils are not recommended for polar elastomers but can be used to good advantage in semipolar elastomers. Naphthenic oils do not need to be labeled as carcinogenic if they have been adequately hydro-treated or extracted to meet industry and OSHA standards. 

Table 12.6 has the ASTM D 2226 Classification and also shows the limits for classifying process oils by VGC. All aromatic process oils must be labeled as potential carcinogens. Paraffinic types and treated naphthenic do not need to be labeled. There is a growing availability problem with naphthenic process oils due to a shortage of naphthenic-rich crude and the exit of producers not able to justify the capital cost of solvent or hydro-treatment. This will result in increases in the cost of naphthenic oils for use in the rubber industry in the near future. 

ATM— never use a paraffinic or low naphthenic process oil above 5 phr when compounding with castor oil factice since they are incompatible and exudation occurs immediately. 

Most types of CR are best plasticized with naphthenic process oils of varying viscosities and medium to high naphthenic/aromatic content. The trick in CR formulating after picking the appropriate grade is to balance the processability, heat resistance, UV resistance, crystallinity, and stress-strain properties through the selection of the plasticizer. This usually means a combination of vegetable oil, monoester, and process oil and becomes a trial and error exercise. 

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