Lubricant compositions including a polymerizable-acid graft polymer as a corrosion inhibitor

1 . A lubricant composition comprising:

an oil lubricant comprising a mineral oil; and

a corrosion inhibitor comprising a polymerizable-acid graft polymer comprising from about 3.0% to about 35% by weight of an unsaturated grafting acid and an alkylene oxide polymer backbone, the alkylene oxide polymer backbone having the following formula:

wherein each R′ is independently selected from the group consisting of a hydrogen atom, hydrogen radicals, and acyl radicals;

wherein R″ is independently selected from the group consisting of a hydrogen atom, hydrogen radicals, amine-containing radicals, and acyl radicals;

wherein each “n” has, independently, a value of from 2 to 4;

wherein each “Z” has, independently, a value of from 4 to about 1800; and

wherein “a” has a value of from 1 to 4.

2 . The lubricant composition of claim 1 , wherein R′ and R″ are not both a hydrogen atom.

3 . The lubricant composition of claim 1 , wherein the grafting acid is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methylpropylsulfonic acid (AMPS), 2-methacrylamido-2-methylpropylsulfonic acid, styrene sulfonic acid, vinylsulfonic acid, ethylene glycol methacrylate phosphate, vinyl phosphonic acid and mixtures thereof.

4 . The lubricant composition of claim 1 , wherein “n”=2 or 3;

wherein “a” has a value of 1;

wherein each R′ or R″ independently selected from the group consisting of a hydrogen atom, hydrogen radicals, and acyl radicals; and

wherein the alkylene oxide polymer backbone is either an ethylene oxide (“EO”) or propylene oxide (“PO”) polymer.

5 . The lubricant composition of claim 1 , wherein the alkylene oxide polymer backbone is selected from the group consisting of oxyethylene (“EO”) and oxypropylene (“PO”).

6 . The lubricant composition of claim 1 , wherein the alkylene oxide polymer backbone is a copolymer of EO and PO polymers having a weight ratio of from about 0:100 to about 100:0 of EO:PO, or from about 90:10 to about 10:90 of EO:PO, or from about 75:25 to about 25:75 of EO:PO.

7 . The lubricant composition of claim 1 , wherein the polymer has an average molecular weight between approximately 1500 Daltons and approximately 80000 Daltons.

8 . The lubricant composition of claim 1 , wherein the grafting acid is acrylic acid (10 wt. %), and the alkylene oxide polymer backbone is poly(oxyethylene-oxypropylene) having a weight ratio of oxyethylene (“EO”) to oxypropylene (“PO”) of 50:50.

9 . The lubricant composition of claim 1 , wherein the lubricant composition comprises from 0.5 wt. % to 20 wt. % corrosion inhibitor.

10 . A method for reducing corrosion comprising:

exposing a metal component to a solution comprising the lubricant composition of claim 1 and (meth)acrylic acid, wherein the lubricant composition reduces metal corrosion.

11 . The method of claim 10 , wherein the solution may comprise co-solvent.

12 . The method of claim 11 , wherein the co-solvent comprises carboxylic acid, alcohol, or combinations thereof.

13 . The method of claim 12 , wherein the alcohol comprises methanol.

14 . The method of claim 11 , wherein the metal component comprises bronze packing rings.

15 . The method of claim 14 , wherein the bronze packing rings are part of a compressor.

16 . The method of claim 15 , wherein the bronze packing rings are part of a compressor unit utilized in a high pressure polyethylene reactor.

17 . A free-radical polymerization process comprising:

polymerizing ethylene monomer and optionally (meth)acrylic acid comonomer in the presence of the lubricant composition of claim 1 via free radical polymerization in a polyethylene reactor having a compressor with bronze packing rings and at a pressure of at least 100 MPa.