Lubricant Additives

304 Lubricant Additives: Chemistry and Applications

Figures 10.17 through 10.20 summarize VM/PPD effects on MRV viscosity for each base oil

type. In these graphs, the letter Y adjacent to a vertical bar denotes a yield stress failure. For the

API Group I base oil B1 (SAE 5W-30, Figure 10.17), only PPD-3 is effective with all three viscosity

modifi ers. Both VM-1 and VM-3 suffer yield stress failures with at least one PPD. In the 15W-40

formulation, VM-3 exhibits yield stress behavior with all four PPDs, even in one case in which the

MRV viscosity is quite low (PPD-1). In the author’s experience, it is quite unusual to observe yield

stress failures in the MRV test when viscosity is below ∼40,000 cP.

FIGURE 10.17 Rheological results for oil B1. SAE 5W-30 (left) and SAE 15W-40 (right).

PPD-1PPD-2

PPD-3PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (cP) at

−^35

°C Y

Y

Y

PPD-1PPD-2

PPD-3PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (cP) at

−^25

°C

Y

YY Y

FIGURE 10.18 Rheological results for oil B2. SAE 5W-30 (left) and SAE 15W-40 (right).

PPD-1PPD-2

PPD-3PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (

cP) at

−^35

°C

Y

Y

PPD-1PPD-2

PPD-3PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (

cP) at

−^25

°C

Y

FIGURE 10.19 Rheological results for oil B3. SAE 5W-30 (left) and SAE 15W-40 (right).

PPD-1PPD-2

PPD-3PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (

cP) at

−^35

°C

Y

Y

PPD-1PPD-2PPD-3

PPD-4

VM-1

VM-2

VM-3

0

20,000

40,000

60,000

80,000

MRV viscosity (

cP) at

−^25

°C

Y

CRC_59645_Ch010.indd 304CRC_59645_Ch010.indd 304 12/6/2008 10:10:17 AM12/6/2008 10:10:17 AM