Lubricant Additives

306 Lubricant Additives: Chemistry and Applications

deposits [1,2], but the performance additive can be formulated to compensate for these effects.

Kleiser et al. [124] ran a taxicab fl eet test designed to compare the performance of a nonfunctional-

ized OCP viscosity modifi er with a highly dispersant-functionalized OCP (HDOCP) as well as to

test other oil formulation effects. They were surprised to fi nd that SAE 5W-30 oil containing a higher

concentration of non-DOCP showed statistically better engine deposit control when compared to a

similar SAE 15W-40 oil with lower polymer content. They also observed signifi cant improvements

in sludge and va r nish ratings attr ibuted to the use of HDOCP. Others have also repor ted that DOCPs

can be benefi cial in preventing buildup of deposits in laboratory engines such as the Sequence VE

[125], VD [1], and Caterpillar 1H2/1G2 [1] tests. These authors found that engine oils containing

certain DOCPs need less ashless dispersant to achieve an acceptable level of engine cleanliness

than NOCPs. The actual level of deposit prevention is highly infl uenced by the functionalization

chemistry as well as the number of substituents per 1000 backbone carbon atoms, as shown in

Table 10.13 (MFOCP = Multi-functional OCP).

10.6 MANUFACTURERS, MARKETERS, AND OTHER ISSUES

10.6.1 EP/EPDM MANUFACTURERS

EP copolymers and EPDM terpolymers are manufactured by a number of companies around the

globe. Table 10.14 [126] contains a listing of those with production capacity >30,000 metric tons/

year (£65 million per annum). Not all are necessarily supplying rubber into the viscosity modifi er

market. The vast majority of the capacity goes into other applications such as automotive (sealing

systems, radiator hoses, injection molded parts), construction (window gaskets, roofi ng/sheeting,

cable insulation, cable fi ller), and plastics modifi cation.

Various grades are often classifi ed by melt viscosity, EP ratio, diene type and content, and

physical form and fi ller type and level (carbon black, pigments, or extender oils). Melt viscosity is

measured by two main techniques—Mooney viscosity (ASTM D1646 or ISO 289) and melt index

(ASTM D1238 or ISO 1133-1991, also called melt-mass fl ow rate). Mooney viscosity is directly pro-

portional to molecular weight, whereas melt index is inversely proportional to molecular weight.

TABLE 10.13

120 h Caterpillar 1H2 Piston Deposit Ratings of SAE

10W-40 Oils Formulated with N-Vinyl Pyrollidone-

Grafted OCPs

Sample Nitrogen (wt%) TGF WTD

OCP 0 – > 800

MFOCP5 0.3 46 244

MFOCP6 0.5 39 173

MFOCP7 0.7 47 149

MFOCP6a 0.26 28 156

MFOCP2a 0.28 11 139

Note: TGF, top groove fi ll rating; WTD, weighted total (piston) demerits

rating.

a OCP grafted with maleic anhydride and subsequently reacted with amines.

Source: Adapted from Spiess, G.T., Johnston, J.E., and VerStrate, G., Addit.

Schmierst. Arbeitsfl uessigkeiten, Int. Kolloq., 5th, 2, 8.10-1, Tech.

Akad. Esslingen, 1986.

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