Copolymers of ethylene and ethylenically unsaturated monomers, process for their preparation and distillate oil containing said copolymers
AssigneeExxon Research & Engineering Co.
InventorsMax J. Wisotsky, Norman Tunkel
Life of this patent
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Abstract
Polymers of 1,000 to 50,000 and preferably of 1,000 to 2,900 number average molecular weight, comprising 3 to 40 molar proportions of ethylene per molar proportion of an ethylenically unsaturated monomer, are prepared by free radical catalysis in a solvent at temperatures of less than 130.degree. C. in order to minimize ethylene branching, for use as wax crystal modifying agents, e.g. pour depressants and flow improvers for distillate mineral oil, e.g. middle distillate fuel oil.
Claims8
A distillate petroleum fuel oil boiling in the range of 250.degree. F. to 750.degree. F. containing about 0.001 to 2 wt. % of a wax crystal modifier which has a number average molecular weight of about 1,000 to 50,000 and is a copolymer consisting of 3 to 40 molar proportions of ethylene and one molar proportion of ester of the general formula:
- ##STR2## wherein:
- (a) R.sub.1 is selected from the group consisting of hydrogen and methyl radicals;
- (b) R.sub.2 is selected from the group consisting of --OOCR.sub.4 and --COOR.sub.4 groups;
- (c) R.sub.3 is hydrogen, and
- (d) R.sub.4 is a C.sub.1 to C.sub.4 alkyl group;
- which copolymer has less than 6 methyl terminating side branches per 100 methylene groups other than methyl groups on said ester, said copolymer being prepared by copolymerizing said monomers in an inert solvent by free radical catalysis at a temperature of about 70.degree. to 130.degree. C. using a catalyst having a half life at 130.degree. C. under 1 hour and under pressure of 500 to 10,000 psi.
A distillate petroleum fuel oil boiling in the range of 250.degree. F. to 750.degree. F. containing about 0.001 to 2 wt. % of a wax crystal modifier which has a number average molecular weight of about 1,000 to 50,000 and is a copolymer consisting of 3 to 40 molar proportions of ethylene and one molar proportion of ester of the general formula:
- ##STR3## wherein:
- (a) R.sub.1 is selected from the group consisting of hydrogen and methyl radicals;
- (b) R.sub.2 is selected from the group consisting of --OOCR.sub.4 and --COOR.sub.4 groups;
- (c) R.sub.3 is hydrogen, and
- (d) R.sub.4 is a C.sub.1 to C.sub.4 alkyl group;
- which copolymer is characterized by about two methyl terminating side branches per 100 methylene groups other than methyl groups on said ester.
Dependencies are inferred from the claim text.