| 摘要 |
The invention is an improvement in wide viscosity range multigrade lubricants of the type having a mineral oil base into which is added a viscosity index improver and a wear enhancer package and, more specifically, in the viscosity index improver which is used. The viscosity index improver mixture of contains (a) 85 to 99.5% by weight, preferably 91%-95% by weight, of low molecular weight ethylene-propylene copolymers; and (b) 0.5 to 15% by weight, preferably 5% to 9% by weight, of an esterified alkenyl-vinyl polymer pour point depressant to make 100% total amount of (a) and (b). Normally, this mixture will be contained in the base lubricant in an amount of about 1% to 95% by weight, preferably 1% to 25% by weight or 1 to 20% by weight and, most preferably, either 1-5% or 3-10% depending on the desired viscosity properties. To ensure the effect of the compounds in the final mixture, the pour point depressant component (b) should be present in the multigrade lubricant in an amount of at least about 0.1%, preferably 1.5%, and the ethylene-propylene copolymer component (a) should be present in an amount of at least 2% and preferably 25-35%.
|
