A lubricant composition containing a polymerizable acid graft polymer as a corrosion inhibitor

Abstract

Embodiments of the lubricating oil composition may include a lubricating oil and a corrosion inhibitor, and the corrosion inhibitor may include a polymerizable acid graft polymer that may include from about 3.0 wt% to about 35 wt% of an unsaturated grafted acid and an alkylene oxide polymer backbone, and the alkylene oxide polymer backbone has the formula: R”----[(OC n H 2n ) z ----OR’] a (wherein each R’ may be independently selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical, each R” in the formula may be independently selected from the group consisting of a hydrogen atom, a hydrogen radical, an amine-containing radical, and an acyl radical, each “n” in the formula may independently have a value of 2 to 4, each “Z” in the formula may independently have a value of 4 to about 1800, and “a” may have a value of 1 to 4).

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Application No. 63 / 359,586, filed on July 8, 2022, which is hereby incorporated by reference in its entirety.

[0002] Embodiments described herein generally relate to corrosion prevention, and more specifically, to lubricant compositions containing corrosion inhibitors.

Background Art

[0003] Acid Copolymer Resins (ACR) can be used, inter alia, to produce filling materials, building panels, and water pipes. Due to this practicality, there is a global demand for ACR. The production of ACR often involves the use of corrosive materials. Over time, these corrosive materials can corrode the components of the ACR production train, so the replacement of these components becomes necessary. The replacement of these components can increase the cost of ACR production. Therefore, it is necessary to improve the production of ACR, and more specifically, it is necessary to improve the protection from the effects of corrosion of the ACR production train.

Summary of the Invention

[0004] Embodiments of the present disclosure meet this need by utilizing a polymerizable acid graft polymer in a lubricant composition.

[0005] According to at least one embodiment of the present disclosure, a lubricant composition is provided. The lubricant composition includes an oil lubricant and a corrosion inhibitor including a polymerizable acid graft polymer containing from about 3.0 wt% to about 35 wt% of an unsaturated grafted acid and an alkylene oxide polymer backbone, wherein the alkylene oxide polymer backbone has the following formula:

[0006]

Chemical Formula

[0007] Additional features and advantages are described in the following "Detailed Description of the Invention", some of which will be readily apparent to those skilled in the art from that description, or will be recognized by practicing the embodiments described in the specification including the drawings, the following "Detailed Description of the Invention", and the "Claims". **Brief Description of the Drawings**

[0008]

Figure 1

[0009] When explaining the simplified schematic diagram of FIG. 1, numerous valves, temperature sensors, electronic controllers, etc. that can be used and are well known to those skilled in the art are not included. However, it should be understood that these components are within the scope of the present disclosure.

[0010] Here, various embodiments are referred to in more detail, some of which are illustrated in the accompanying drawings. **Detailed Description of the Invention**

[0011] Here, specific embodiments of the present application are described. However, the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments described in the present disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0012] This disclosure relates to lubricant compositions. For example, as described herein, a lubricant composition can include a lubricating oil and a corrosion inhibitor. The corrosion inhibitor can include a polymerizable acid graft polymer that includes from about 3.0 wt% to about 35 wt% unsaturated grafted acid and an alkylene oxide polymer backbone. The alkylene oxide polymer backbone can have the following formula.

[0013] [Chemical Formula]

[0014] Each R' in the formula can be independently selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical. Each R" in the formula can be independently selected from the group consisting of a hydrogen atom, a hydrogen radical, an amine-containing radical, and an acyl radical. Each "n" in the formula can independently have a value from 2 to 4. Each "Z" in the formula can independently have a value from 4 to about 1800. "a" in the formula can have a value from 1 to 4.

[0015] As used herein, the term "polymerizable acid graft polymer" refers to a segmented copolymer that includes a linear backbone polymer and randomly distributed branches of another acid polymer. The linear backbone polymer can be a poly(alkylene oxide) compound. The poly(alkylene oxide) compound can be produced by reacting an alkylene oxide or a mixture of alkylene oxides added continuously or in combination with an alcohol. Such an alcohol can be monovalent or polyvalent and has the formula R"(OH) a(wherein R” is selected from the group consisting of a hydrogen atom, a hydrogen radical, an amine-containing radical, and an acyl radical, and “a” has a value of 1 to 4). Such alcohols include methanol, ethanol, propanol, butanol, ethylene glycol, glycerol, monoethyl ether of glycerol, dimethyl ether of glycerol, sorbitol, 1,2,6-hexanetriol, trimethylolpropane, and other alcohols having corresponding formulas are contemplated herein. Grafting of the polymerizable acid monomer to the poly(oxyalkylene) compound to form the polymerizable acid graft polymer can be carried out by free radical polymerization.

[0016] In one or more embodiments, the lubricant composition may include an oil lubricant. The oil lubricant may include at least one oil and may contain one or more additives, such as one or more lubricants. Additives may be added to improve lubricity, flow characteristics, thermal stability, and / or other properties. In one or more embodiments, at least one oil may be a viscous liquid derived from petroleum having an increased viscosity compared to the viscosity of water at the same temperature and pressure. At least one oil may provide lubrication and friction reduction between the moving surfaces of a rotary mechanism and / or a reciprocating mechanism. In one or more embodiments, the oil may be one or more mineral oils and polyalkylene glycol base oils.

[0017] In some embodiments, the oil is 50 mm 2 / s to 200 mm 2 / s kinematic viscosity at 40 °C. For example, the oil may have a kinematic viscosity of 50 mm 2 / s to 100 mm 2 / s, 100 mm 2 / s to 150 mm 2 / s, 150 mm 2 / s to 200 mm 2 / s, or any combination of these ranges of kinematic viscosity.

[0018] As described herein, in one or more embodiments, the lubricant composition may include a corrosion inhibitor. In some embodiments, the lubricant composition may include a corrosion inhibitor in an amount of from 0.5 wt% to about 20 wt%. For example, the lubricant composition may include a corrosion inhibitor in an amount of from 0.5 wt% to 1 wt%, from 1 wt% to 5 wt%, from 5 wt% to 10 wt%, from 10 wt% to 15 wt%, from 15 wt% to 20 wt%, or any combination of amounts within these ranges. In some embodiments, the lubricant composition may include a corrosion inhibitor in an amount of from 1 wt% to 17.5 wt%, from 1.5 wt% to 15 wt%, from 2 wt% to 12.5 wt%, or from 2.5 wt% to 10 wt%. In some embodiments, the lubricant composition may include a polymerizable acid graft polymer as described herein in an amount of from 2.5 wt% to 10 wt%.

[0019] In one or more embodiments, the corrosion inhibitor may include the above-described polymerizable acid graft polymer. As described above, the alkylene oxide polymer backbone may have the following formula.

[0020] [Chemical formula]

[0021] Each R' may independently be selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical. R'' may independently be selected from the group consisting of a hydrogen atom, a hydrogen radical, an amine-containing radical, and an acyl radical. Each "n" may independently have a value from 2 to 4. Each "Z" may independently have a value from 4 to about 1800. In the formula, "a" may have a value from 1 to 4. In some embodiments, the lubricant composition may include a corrosion inhibitor in which R' and R'' are not both hydrogen atoms. In one or more embodiments, "n" is 2 or 3, "a" has a value of 1, and R' and R'' are selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical. In one embodiment, the alkylene oxide polymer backbone is either an ethylene oxide ("EO") polymer or a propylene oxide ("PO") polymer.

[0022] In another embodiment, the corrosion inhibitor may include an alkylene oxide polymer backbone selected from the group consisting of ethylene oxide ("EO") and propylene oxide ("PO").

[0023] In one or more embodiments, the alkylene oxide polymer backbone is a copolymer of an EO polymer and a PO polymer having a weight ratio of EO:PO of from about 0:100 to about 100:0. For example, the alkylene oxide polymer backbone is an EO polymer and a PO polymer having a weight ratio of EO:PO of about 0:100, about 10:90, about 20:80, about 30:70, about 40:60, about 50:50, about 60:40, about 70:30, about 80:20, about 90:10, or about 100:0. In some embodiments, the alkylene oxide polymer backbone is a copolymer of an EO polymer and a PO polymer having a weight ratio of EO:PO of from about 90:10 to about 10:90, or from about 75:25 to about 25:75.

[0024] In one or more embodiments, the polymerizable acid graft polymer may have an average molecular weight of from about 1500 Daltons to about 80000 Daltons. For example, the polymerizable acid graft polymer may have an average molecular weight of from about 1500 Daltons to about 5000 Daltons, from about 5000 Daltons to about 10000 Daltons, from about 10000 Daltons to about 20000 Daltons, from about 20000 Daltons to about 30000 Daltons, from about 30000 Daltons to about 40000 Daltons, from about 40000 Daltons to about 50000 Daltons, from about 50000 Daltons to about 60000 Daltons, from about 60000 Daltons to about 70000 Daltons, from about 70000 Daltons to about 80000 Daltons, or any combination of these ranges. In some embodiments, the polymerizable acid graft polymer may have an average weight of from about 1500 Daltons to about 20000 Daltons.

[0025] As disclosed herein, in one or more embodiments, the polymerizable acid-grafted polymer can contain from about 3.0 wt% to about 35 wt% unsaturated grafted acid. For example, the polymerizable acid-grafted polymer can contain from about 3.0 wt% to about 5.0 wt%, from about 5.0 wt% to about 10 wt%, from about 10 wt% to about 15 wt%, from about 15 wt% to about 20 wt%, from about 20 wt% to about 25 wt%, from about 25 wt% to about 30 wt%, from about 30 wt% to about 35 wt%, or any combination of these ranges. In some embodiments, the polymerizable acid-grafted polymer can constitute from about 4.0 wt% to about 30 wt% or from about 5.0 wt% to about 25 wt%. Without being bound by theory, surprisingly, this grafting level has been found to correlate with an increase in corrosion resistance, as further explained below.

[0026] In one or more embodiments, the unsaturated grafted acid can be selected from one or more of acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-acrylamido-2-methylpropyl sulfonic acid (AMPS), 2-methacrylamido-2-methylpropyl sulfonic acid, styrene sulfonic acid, vinyl sulfonic acid, ethylene glycol methacrylate phosphate, vinyl phosphonic acid, and mixtures thereof.

[0027] In one or more embodiments, the corrosion inhibitor can include a polymerizable acid-grafted polymer in which the grafted acid is acrylic acid and the alkylene oxide polymer backbone is poly(oxyethylene-oxypropylene) with a weight ratio of oxyethylene to oxypropylene of 50:50.

[0028] In one or more embodiments, the corrosion inhibitor can be an acrylic acid-grafted ethylene oxide-propylene oxide copolymer. For example, the corrosion inhibitor can be UCON™ EPML-483 manufactured by Dow.

[0029] In one or more embodiments, the lubricant composition can be used in a method of reducing corrosion that includes exposing a metal part to a solution containing the lubricant composition and (meth)acrylic acid, and the lubricant composition reduces metal corrosion. As used in this disclosure, the term “(meth)acrylic acid” can be used to refer to either methacrylic acid or acrylic acid, or both.

[0030] In one or more embodiments, the solution containing the lubricant composition can include a co-solvent. The co-solvent can include a carboxylic acid, an alcohol, or a combination thereof. In some embodiments, the co-solvent can include methanol.

[0031] As described above, the lubricant composition can be used to resist corrosion of metal parts. In one or more embodiments, the metal part can include a bronze packing ring. In one or more embodiments, the bronze packing ring can be part of a compressor. In some embodiments, the bronze packing ring can be part of a compressor unit utilized in a high-pressure polymerization reactor such as that schematically shown in FIG. 1.

[0032] In one or more embodiments, the lubricant composition can be used in a free-radical polymerization process that includes polymerizing an ethylene monomer and optionally (meth)acrylic acid in the presence of the lubricant composition via free-radical polymerization within a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring. The free-radical polymerization process for producing an ethylene-based polymer is typically carried out at a high pressure of at least 100 MPa. For example, the free-radical polymerization process can be carried out at at least 200 MPa, at least 300 MPa, at least 400 MPa, or at least 500 MPa.

[0033] The following definitions can be useful in understanding the operation of an exemplary reactor system that can be suitable for use with the lubricant compositions described herein.

[0034] As used herein, the term "feed" or "feed stream" refers to fresh and / or recycled reactants added at the inlet to the reaction zone to the reaction zone.

[0035] As used herein, the term "reaction zone" refers to a reactor zone where a polymerization reaction is initiated or restarted by the addition of free radicals and / or the decomposition of components to free radicals or components that generate free radicals.

[0036] As used herein, the term "reactor system" refers to the components (equipment) used to polymerize and isolate a polymer. Such components / equipment include, but are not limited to, one or more reactors, a hypercompressor, a primary compressor, and a booster compressor. The reactor system typically includes at least one reactor, such as a tubular reactor, an autoclave reactor, or any combination thereof.

[0037] As used herein, the term "injection point" refers to the location of the inlet of the equipment (used in the polymerization process) where the feed stream is added to the equipment.

[0038] As used herein, the term "pressurize" refers to raising the pressure of a liquid or a feed to a higher pressure level.

[0039] As used herein, the term "compression system" refers to a compression device that raises the pressure of a vapor (e.g., ethylene vapor below or above its critical point) to a higher pressure level. Supplying a comonomer can include pressurizing the reactive comonomer with an ultra-high pressure reciprocating plunger pump and supplying it directly to the reaction zone and / or to the feed stream to the reaction zone, and / or supplying the comonomer by a combination with pressurization by a high-pressure pump, and further compressing it via a reciprocating plunger compressor (e.g., a hypercompressor, a primary compressor, and / or a booster compressor).

[0040] As used herein, the term "compression" refers to raising the pressure of a vapor (e.g., ethylene vapor below or above its critical point) to a higher pressure level.

[0041] A booster compressor is, for example, a device that compresses a low-pressure recycle coming from a low-pressure separator to the pressure level required at the inlet side of a primary compressor. This compression may be carried out in one or more compression stages and may be combined with intercooling. The booster compressor may consist of a single or multiple compressor frames and may potentially be combined with a primary compressor frame.

[0042] A primary compressor is, for example, a device that compresses a) fresh incoming ethylene and / or b) a low-pressure recycle coming from a booster compressor, respectively, to the pressure level required at the inlet side of a hypercompressor. This compression may be carried out in one or more compression stages and may be combined with intercooling. The primary compressor may consist of a single or multiple compressor frames and may potentially be combined with a booster compressor frame.

[0043] A hypercompressor or secondary compressor is, for example, a device that compresses a monomer coming from a primary compressor to the pressure level required for supply to a reactor at its inlet pressure setpoint. This compression may be carried out in one or more compression stages and may be combined with intercooling. The hypercompressor typically comprises a plunger reciprocating compressor and may consist of a single or multiple compressor frames.

[0044] Referring now to FIG. 1, an exemplary reactor system that may be suitable for use with the lubricant compositions described herein is schematically shown. It should be understood that not all parts of FIG. 1 are to be construed as essential to the claimed subject matter. Further, while the lubricant compositions in the appended claims are described herein in the context of FIG. 1, such listed compositions should be understood to be adaptable to other systems as would be understood by one of ordinary skill in the art.

[0045] Figure 1 shows a generalized flow scheme of a high-pressure polymerization process using a reactor system that includes a reactor 26, which can be a tubular reactor, an autoclave reactor, or a combination of a tubular reactor and an autoclave reactor. Flow (1) represents a fresh monomer feed that is compressed by a primary compressor (22) together with the outlet of a booster compressor (20) into flow (2). The fresh monomer feed can include ethylene. Flow (2) is combined with the high-pressure recycle flow (7) from a high-pressure separator (28) at the hypercompressor inlet flow (3) and supplied to the suction of a hypercompressor (24). The hypercompressor compresses the monomer feed stream to a level sufficient to supply the reactor (26). Flow 4 represents the compressed monomer feed stream supplied to the reactor (26). The high-pressure separator (28) separates the product stream (5) into a polymer-rich stream (6) and an unreacted monomer-rich stream (7). Flow (7) is recycled for reuse in the process, and flow (6) is sent to a low-pressure separator (30). The low-pressure separator (30) separates the vapor (6) into a monomer stream (8) flowing to the booster compressor (20) and a polymer stream (9) withdrawn for further processing.

[0046] In one or more embodiments, the lubricant compositions described herein can be utilized in a hypercompressor (hyper). For example, the lubricant composition can be exposed to the metal parts of the hypercompressor (hyper). In some embodiments, the metal parts of the hypercompressor (hyper) can comprise bronze packing rings.

[0047] Test Methods Corrosion Test The corrosion test was carried out at 20 °C with 8.8 g / cm 3Performed using 936 bearing bronze coupons having a density of. The bronze coupons were cut to a diameter of 1.27 cm and a thickness of 0.32 cm. The tests were conducted inside a glove box. The reagents were degassed and dried as necessary before being placed in the glove box. All experiments were repeated 5 times and the averages were reported. Pre-measured coupons were added to 40 mL vials equipped with pressure release caps. Next, the reagents were added to the vials and the pressure release caps were secured. The vials were then removed from the glove box and photographs of the vials were taken. The vials were then placed inside a heating block and heated at 100 °C for 2 weeks. After 2 weeks, the vials were removed from the heating block and cooled. Once the vials had cooled to room temperature, the coupons were removed from the vials using tweezers and placed on a chemwipe. The coupons were rinsed with tetradecane on a metal dish and wiped completely using a metal spatula. The flat end of the spatula was used at an angle of approximately 30° to scrape off any corrosion or deposits on the surface of the coupons. Care was taken not to apply maximum pressure to the coupons during scraping to avoid gouging the surface of the coupons. The coupons were rinsed with clean tetradecane and wiped with a chemwipe. The washed coupons were placed separately into 20 mL vials. The vials containing the washed coupons were placed in a vacuum oven at 160 °C overnight to dry. Next, the dry coupons were weighed. The difference between the dry coupon weight and the starting coupon weight was measured and recorded.

[0048] Corrosion rate The corrosion rate was measured using the following formula, where the weight loss is the difference between the dry coupon weight and the starting coupon weight, the alloy density is 8.8 g / cm 3 and the exposed area of the coupon was measured by considering the coupon as a cylinder, and the exposed area was calculated as the area of the cylinder. The coupon had a diameter of 1.27 cm and a thickness of 0.32 cm for an exposed area of 3.86 cm 2 The exposure time was 336 hours and K is the K factor. The values of the alloy density and the K factor were collected from the literature.

[0049]

Number

[0050] Corrosion prevention Corrosion prevention was measured and the corrosion prevention rate was calculated using the following formula. The corrosion rate that was not prevented was calculated from the corrosion rate of the coupon in the absence of the inhibitor. The corrosion rate that was prevented was calculated from the corrosion rate of the test piece to which the inhibitor was added.

[0051]

Number

Example

[0052] The embodiments will become clearer from the following examples.

[0053]

Table 1

[0054] Table 1 shows the composition of the lubricant compositions tested for corrosion prevention performance. A corrosion inhibitor test was conducted using a formulation having a lubricating oil, methanol, methacrylic acid, and optionally a corrosion inhibitor. The formulation components were mixed at room temperature. The lubricating oil used was Hydrobrite 380, a commonly available white mineral oil produced by Sonneborn. The inhibitors used were UCON™ EPML 483, an acrylic acid-grafted ethylene oxide-propylene oxide copolymer, and UCON™ 50-HB-5100, a non-grafted ethylene oxide-propylene oxide copolymer. Both UCON™ EPML 483 and UCON™ 50-HB-5100 are commercially available from Dow Inc. (Midland, MI). The amount of inhibitor added in each experiment was calculated as a weight percentage of the Hydrobrite 380 lubricating oil.

[0055]

Table 2

[0056]

Table 3

[0057] Referring to the corrosion prevention results in Table 2 and Table 3, the experiments using EPML 483 (i.e., Experiments 2 to 4) show significantly less corrosion than the comparative examples without EPML 483 such as Comparative Examples A and B. In addition, Tables 2 and 3 show that the corrosion prevention increased as the amount of EPML 483 was increased up to 10%. Briefly speaking, Tables 2 and 3 show that EPML 483 exhibited excellent corrosion prevention against methanol and methacrylic acid when combined with a lubricating oil. Furthermore, Tables 2 and 3 show that the addition of a non-grafted ethylene oxide-propylene oxide copolymer as in Comparative Example B had little effect on the corrosion prevention performance of the lubricant composition. This indicates that the acid grafting of the ethylene oxide-propylene oxide copolymer improved the corrosion prevention characteristics of the copolymer.

[0058] In a first aspect of the present disclosure, the lubricant composition may include an oil lubricant and a corrosion inhibitor including a polymerizable acid graft polymer containing about 3.0 wt% to about 35 wt% of an unsaturated grafted acid and an alkylene oxide polymer backbone, and the alkylene oxide polymer backbone has the formula (I):

[0059]

Chemical formula

[0060] The second aspect of the present disclosure may include the first aspect, where neither R' nor R'' is a hydrogen atom.

[0061] The third aspect of the present disclosure may include any of the foregoing aspects, where the grafted 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, styrenesulfonic acid, vinylsulfonic acid, ethylene glycol methacrylate phosphate, vinylphosphonic acid, and mixtures thereof.

[0062] The fourth aspect of the present disclosure may include any of the foregoing aspects, where "n" = 2 or 3, "a" has a value of 1, each R' or R'' is independently selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical, and the alkylene oxide polymer backbone is either an ethylene oxide ("EO") polymer or a propylene oxide ("PO") polymer.

[0063] The fifth aspect of the present disclosure may include any of the foregoing aspects, where the alkylene oxide polymer backbone is selected from the group consisting of oxyethylene ("EO") and oxypropylene ("PO").

[0064] The sixth aspect of the present disclosure may include any of the foregoing aspects, where the alkylene oxide polymer backbone is a copolymer of an EO polymer and a PO polymer having a weight ratio of EO:PO of about 0:100 to about 100:0, or about 90:10 to about 10:90, or about 75:25 to about 25:75.

[0065] The seventh aspect of the present disclosure may include any of the foregoing aspects, where the polymer has an average molecular weight of about 1500 daltons to about 80000 daltons.

[0066] The eighth aspect of the present disclosure may include any of the foregoing aspects, wherein the grafted acid is acrylic acid (10% by weight), and the alkylene oxide polymer backbone is poly(oxyethylene-oxypropylene) having a weight ratio of 50:50 oxyethylene (“EO”) to oxypropylene (“PO”).

[0067] The ninth aspect of the present disclosure may include any of the foregoing aspects, wherein the oil lubricant contains mineral oil.

[0068] The tenth aspect of the present disclosure may include any of the foregoing aspects, wherein the lubricant composition contains 0.5% to 20% by weight of a corrosion inhibitor or 2.5% to 10% by weight of a corrosion inhibitor.

[0069] The eleventh aspect of the present disclosure is a method for reducing corrosion, which includes exposing a metal part to a solution containing the lubricant composition and (meth)acrylic acid described in any of the foregoing aspects, wherein the lubricant composition reduces metal corrosion.

[0070] The twelfth aspect of the present disclosure may include the eleventh aspect, wherein the solution may contain a co-solvent.

[0071] The thirteenth aspect of the present disclosure may include the twelfth aspect, wherein the co-solvent contains a carboxylic acid, an alcohol, or a combination thereof.

[0072] The fourteenth aspect of the present disclosure may include the thirteenth aspect, wherein the alcohol contains methanol.

[0073] The fifteenth aspect of the present disclosure may include the twelfth to fourteenth aspects, wherein the metal part contains a bronze packing ring.

[0074] The sixteenth aspect of the present disclosure may include the fifteenth aspect, wherein the bronze packing ring is part of a compressor.

[0075] A seventeenth aspect of the present disclosure may include the sixteenth aspect, wherein the bronze packing ring is part of a compressor unit utilized in a high-pressure polyethylene reactor.

[0076] An eighteenth aspect of the present disclosure may include a free-radical polymerization process that includes polymerizing an ethylene monomer and optionally a (meth)acrylic acid comonomer in the presence of a lubricant composition according to any one of the first to eleventh aspects via free-radical polymerization in a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring.

[0077] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope disclosed herein. The scope disclosed herein should be construed to include all within the scope of the appended claims and their equivalents, as modifications, combinations, sub-combinations, and variations of the disclosed embodiments incorporating the spirit and substance disclosed herein would be conceivable to those skilled in the art.

[0078] For the purpose of defining the present technology, the transitional phrase "consisting of" may be introduced into a claim as a closed - preamble term that limits the claim to the recited components or steps and any naturally occurring impurities. For the purpose of defining the present technology, the transitional phrase "consisting essentially of" may be introduced into a claim to limit one or more claims to the recited elements, components, materials, or method steps, and any unrecited elements, components, materials, or method steps that do not substantially affect the novel features of the claimed subject matter. The transitional phrases "consisting of" and "consisting essentially of" can be construed as subsets of non - limiting transitional phrases such as "comprising" and "including", and thus any use of a non - limiting phrase to introduce a listing of a series of elements, components, materials, or steps should be construed to also disclose a listing of a series of elements, components, materials, or steps using the closed terms "consisting of" and "consisting essentially of". For example, a description of a composition "comprising" components A, B, and C should be construed to also disclose a composition "consisting of" components A, B, and C, as well as a composition "consisting essentially of" components A, B, and C. Any quantitative value expressed in the present application can be considered to include open - end embodiments that are consistent with the transitional phrase "comprising" or "including", as well as closed or partially - closed embodiments that are consistent with the transitional phrases "consisting of" and "consisting essentially of".

[0079] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. The verb "comprises" and its conjugations are to be construed as referring to elements, components, or steps in a non-exclusive manner. The recited elements, components, or steps may be present, utilized, or combined with other elements, components, or steps not expressly recited.

[0080] It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and that all combinations of ranges formed from all the recited quantitative values of a given property are contemplated in the present disclosure. The subject matter disclosed herein has been described in detail with reference to particular embodiments. It should be understood that any detailed description of components or features of an embodiment does not necessarily imply that such components or features are essential to that or any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. A lubricant composition comprising: an oil lubricant; and a corrosion inhibitor comprising a polymerizable acid graft polymer containing an unsaturated grafted acid and an alkylene oxide polymer backbone of about 3.0 wt% to about 35 wt%, wherein the alkylene oxide polymer backbone has the following formula: 【Chemical 1】 (wherein each R' is independently selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical, R" is independently selected from the group consisting of a hydrogen atom, a hydrogen radical, an amine-containing radical, and an acyl radical, each "n" independently has a value of 2 to 4, each "Z" independently has a value of 4 to about 1800, and "a" has a value of 1 to 4).

2. The lubricant composition according to claim 1, wherein neither R' nor R" is a hydrogen atom.

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

4. "n" = 2 or 3, "a" has a value of 1, each R' or R" is independently selected from the group consisting of a hydrogen atom, a hydrogen radical, and an acyl radical, and the alkylene oxide polymer backbone is either an ethylene oxide ("EO") polymer or a propylene oxide ("PO") polymer. The lubricant composition according to any one of claims 1 to 3.

5. The lubricant composition according to any one of claims 1 to 4, wherein the alkylene oxide polymer backbone is selected from the group consisting of oxyethylene ("EO") and oxypropylene ("PO").

6. The lubricant composition according to any one of claims 1 to 5, wherein the alkylene oxide polymer backbone is a copolymer of an EO polymer and a PO polymer having a weight ratio of EO:PO of about 0:100 to about 100:0, or about 90:10 to about 10:90, or about 75:25 to about 25:

75.

7. The lubricant composition according to any one of claims 1 to 6, wherein the polymer has an average molecular weight of about 1500 daltons to about 80000 daltons.

8. The grafted acid is acrylic acid (10% by weight), and the alkylene oxide polymer skeleton is poly(oxyethylene - oxypropylene) having a weight ratio of 50:50 of oxyethylene ("EO") to oxypropylene ("PO"), the lubricant composition according to any one of claims 1 to 7.

9. The lubricant composition according to any one of claims 1 to 8, wherein the oil lubricant contains a mineral oil.

10. The lubricant composition according to any one of claims 1 to 9, wherein the lubricant composition contains 0.5% to 20% by weight of a corrosion inhibitor or 2.5% to 10% by weight of a corrosion inhibitor.

11. A method for reducing corrosion, comprising exposing a metal part to a solution containing the lubricant composition according to any one of claims 1 to 10 and (meth)acrylic acid, wherein the lubricant composition reduces metal corrosion.

12. The method according to claim 11, wherein the solution may contain a co-solvent.

13. The method according to claim 12, wherein the co-solvent contains a carboxylic acid, an alcohol, or a combination thereof.

14. The method according to claim 13, wherein the alcohol contains methanol.

15. The method according to any one of claims 12 to 14, wherein the metal part contains a bronze packing ring.

16. The method according to claim 15, wherein the bronze packing ring is part of a compressor.

17. The method according to claim 16, wherein the bronze packing ring is part of a compressor unit used in a high-pressure polyethylene reactor.

18. A free radical polymerization process, comprising polymerizing an ethylene monomer and optionally a (meth)acrylic acid comonomer in the presence of the lubricant composition according to any one of claims 1 to 11 via free radical polymerization in a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring.

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