Lubricant composition and method for producing copolymer using the same
A lubricating composition with phenothiazine-based inhibitors and hindered phenol/hydroquinone accelerators effectively suppresses self-polymerization in ethylene-carboxylic acid copolymer production, improving yield and process reliability by regenerating the inhibitor.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SK GEO CENTRIC CO LTD
- Filing Date
- 2024-08-22
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods fail to effectively suppress self-polymerization of ethylene-carboxylic acid copolymers during production, leading to equipment defects and reduced yield, due to the self-reactivity of carboxylic acid compounds at high temperatures.
A lubricating composition comprising a base oil, a phenothiazine-based polymerization inhibitor, and a polymerization inhibitor accelerator with hindered phenol and hydroquinone compounds is used to suppress self-polymerization by regenerating the polymerization inhibitor, maintaining its effectiveness over time.
The lubricating composition efficiently prevents equipment clogging and improves copolymer yield by prolonging the suppression of self-polymerization, enhancing process reliability and efficiency.
Smart Images
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Abstract
Description
[Technical Field]
[0001] This invention relates to a lubricating composition and a method for producing a copolymer using the same. More specifically, it relates to a lubricating composition comprising a base oil and additives, and a method for producing a copolymer using the same. [Background technology]
[0002] For example, ethylene-carboxylic acid copolymers, such as ethylene-acrylic acid copolymers, are used in a variety of applications including sealants, adhesives, packing materials, and optical films.
[0003] Ethylene-carboxylic acid copolymers can be produced by polymerizing ethylene and a carboxylic acid-based compound (e.g., acrylic acid, methacrylic acid, etc.) as a copolymer in a continuous reactor.
[0004] Because carboxylic acid compounds are more self-reactive than ethylene, they can undergo self-polymerization when exposed to high temperatures during the supply process from channels, pumps, compressors, etc.
[0005] In this case, equipment defects such as clogging of pumps, compressors, and flow channels, or blockage of flow channels may occur, which can lead to a decrease in copolymer production yield and make it difficult to uniformly repeat the process.
[0006] Therefore, methods are being studied that use monomers for polymerizing copolymers together with additives to suppress self-polymerization. However, in order to directly block the aforementioned equipment defects, there is a need for the design or research of compositions such as lubricants applied to the equipment to efficiently suppress self-polymerization.
[0007] For example, International Patent Publication WO2016 / 172076 discloses the use of polymerization inhibitors to prevent fouling in polymerization reactions, but it does not disclose designs to prevent self-polymerization at the apparatus and process level as described above. [Prior art documents] [Patent Documents]
[0008] [Patent Document 1] International Patent Publication No. WO2016 / 172076 [Overview of the project] [Problems that the invention aims to solve]
[0009] The objective of the present invention is to provide a lubricating composition that achieves improved process reliability and polymerization efficiency.
[0010] The object of the present invention is to provide a method for producing a copolymer using the lubricating composition. [Means for solving the problem]
[0011] A lubricating composition according to an embodiment of the present invention may include a base oil, a phenothiazine-based polymerization inhibitor, and a polymerization inhibitor accelerator comprising a hindered phenol compound and a hydroquinone compound.
[0012] In some embodiments, the polymerization inhibitor may include a compound represented by the following chemical formula 1.
[0013] [ka]
[0014] In chemical formula 1, R1 to R8 may each independently be hydrogen, a C1-C5 alkyl group, or a C1-C5 alkoxy group.
[0015] In some embodiments, the content of the polymerization inhibitor may be 1 to 2,000 ppm relative to the weight of the base oil.
[0016] In some embodiments, the content of the polymerization inhibitor may be 1 to 10 ppm with respect to the weight of the base oil.
[0017] In some embodiments, the hindered phenol compound can be represented by the following Chemical Formula 2.
[0018]
Chemical formula
[0019] In Chemical Formula 2, R9 to R
[0027] , , ,
[0026] may each be an alkyl group having 1 to 5 carbon atoms.
[0020] In some embodiments, the hindered phenol compound may be butylated hydroxytoluene (BHT).
[0021] In some embodiments, the hydroquinone compound can be represented by the following Chemical Formula 3.
[0022]
Chemical formula
[0023] In Chemical Formula 3, R 12 ~R 16 may each be hydrogen or an alkyl group having 1 to 5 carbon atoms.
[0024] In some embodiments, the hydroquinone compound may be hydroquinone monomethyl ether (MeHQ).
[0025] In some embodiments, the content of the polymerization inhibition accelerator may be 1 to 10% by weight with respect to the weight of the base oil.
[0026] In some embodiments, the lubricating composition may further contain a polar non-aromatic compound.
[0027] In some embodiments, the polar non-aromatic compound may include a fatty acid compound.
[0028] In some embodiments, the content of the polar non-aromatic compound may be more than 1% by weight and 10% by weight or less relative to the weight of the base oil.
[0029] In a method for producing a copolymer according to an embodiment of the present invention, the aforementioned lubricating composition can be injected into the discharge section. A first monomer containing a carboxylic acid monomer can be discharged through the discharge section. The discharged first monomer can be reacted with a second monomer.
[0030] In some embodiments, the second monomer may be an ethylene polymerizable monomer.
[0031] In some embodiments, the injection rate of the lubricating composition into the discharge section may be 25 to 130 kg / hr.
[0032] In some embodiments, the temperature inside the discharge section may be 20 to 120°C, and the discharge pressure from the discharge section may be 1100 to 2500 bar. [Effects of the Invention]
[0033] According to embodiments of the present invention, for example, a polymerization inhibitor such as a phenothiazine compound can be added to the lubricating oil of a pump that discharges a carboxylic acid monomer, and a polymerization inhibitor accelerator containing a hindered phenol compound and a hydroquinone compound can also be added.
[0034] The polymerization inhibitor accelerator can regenerate radicalized phenothiazine compounds and activate the polymerization inhibition mechanism. This allows even a small amount of polymerization inhibitor to maintain the suppression of self-polymerization of carboxylic acid monomers for a long period, improving copolymer yield and preventing clogging of polymerization equipment.
[0035] In some embodiments, the lubricating composition may further contain a polar non-aromatic compound. The polar non-aromatic compound can increase the solubility of the hindered phenol compound and further promote the regeneration of the phenothiazine compound. [Brief explanation of the drawing]
[0036] [Figure 1] Figure 1 is a schematic process flowchart illustrating a method for producing a copolymer according to an exemplary embodiment. [Modes for carrying out the invention]
[0037] Embodiments of the present invention provide a lubricating composition comprising a polymerization inhibitor, a polymerization inhibitor accelerator containing a hindered phenol compound and a hydroquinone compound, and a base oil. Embodiments of the present invention also provide a method for producing a copolymer in which the self-polymerization of monomers can be efficiently suppressed using the lubricating composition.
[0038] The embodiments of the present invention will be described in more detail below with reference to specific experimental examples and drawings. However, the drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to help further understand the technical concept of the present invention. Therefore, the present invention is not to be construed as being limited only to the matters described in the drawings.
[0039] <Lubricating composition> An exemplary lubricating composition comprises a base oil, a polymerization inhibitor, and a polymerization inhibitor accelerator. In some embodiments, the lubricating composition may further contain a polar non-aromatic compound.
[0040] The base oil can be included as the base solvent, diluent, or medium of the lubricating composition. The type of base oil is not particularly limited; lubricating oils used in polymerization equipment, petrochemical facilities, etc., can be used. For example, mineral oil can be used as the base oil.
[0041] The base oil may be included as the remaining amount of the lubricating composition after the components described later have been removed. The "remaining amount" should be understood as a variable amount that is adjusted by the added components.
[0042] Polymerization inhibitors can be included, for example, as components that suppress the self-polymerization of carboxylic acid monomers. According to exemplary embodiments, the polymerization inhibitor may include a phenothiazine compound represented by the following chemical formula 1.
[0043] [ka]
[0044] In chemical formula 1, R1 to R8 may each independently be hydrogen, a C1-C5 alkyl group, or a C1-C5 alkoxy group.
[0045] In some embodiments, the polymerization inhibitor content may be about 2,000 ppm or less relative to the weight of the base oil. If the polymerization inhibitor content exceeds about 2,000 ppm, the environmental risk may increase due to an excessive increase in radical-based active substances, and may even decrease the copolymer yield.
[0046] The content of the polymerization inhibitor is preferably about 1,000 ppm or less, and more preferably about 1 to 10 ppm, relative to the weight of the base oil. Within this range, the regeneration mechanism by the polymerization inhibitor accelerator described later can be more easily realized.
[0047] According to exemplary embodiments, polymerization inhibitors can be used together with the aforementioned polymerization inhibitors. The polymerization inhibitors may include both hindered phenol compounds and hydroquinone compounds.
[0048] The aforementioned hindered phenol compound can be represented by the following chemical formula 2.
[0049] [Chemical formula]
[0050] In Chemical formula 2, R9 to R 11 may each be an alkyl group having 1 to 5 carbon atoms. In a preferred embodiment, R9 may be a normal alkyl (n-alkyl) group, and R 10 and R 11 may each independently be a secondary (sec)-alkyl group, an iso-alkyl group, or a tert-alkyl group. Preferably, R 10 and R 11 may each contain a tert-alkyl group. In one embodiment, the hindered phenol compound may be butylated hydroxytoluene (BHT) represented by the following Chemical formula 2-1.
[0051] [Chemical formula]
[0052] The hydroquinone compound can be represented by the following Chemical formula 3.
[0053] [Chemical formula]
[0054] In Chemical formula 3, R 12 to R 16 may each be hydrogen or an alkyl group having 1 to 5 carbon atoms. In some embodiments, the hydroquinone compound may be hydroquinone monomethyl ether (MeHQ) represented by the following Chemical formula 3-1.
[0055] [Chemical formula]
[0056] The acidic hydrogen contained in the hydroxyl group of the aforementioned hindered phenol compound is transferred to the phenothiazine compound (polymerization inhibitor), allowing the radicalized phenothiazine compound to be regenerated. This increases the lifespan of the phenothiazine compound, and even with a small amount of polymerization inhibitor, the suppression of self-polymerization of carboxylic acid monomers can be efficiently maintained.
[0057] Furthermore, the relatively bulky alkyl group (R) contained in hindered phenol compounds 10 , R 11 The acidity of the hydrogen bonded to the hydroxyl group increases, for example, by the tert-butyl group, which facilitates hydrogen transfer.
[0058] Furthermore, the relatively bulky alkyl group improves solubility in the base oil, allowing for the uniform maintenance of the regenerative effect of the polymerization inhibitor of hindered phenol compounds.
[0059] Hindered phenol compounds may have relatively low solubility in carboxylic acid monomer solutions (e.g., acrylic acid). According to exemplary embodiments, hindered phenol compounds can be used together with hydroquinone compounds that have high solubility in carboxylic acid monomer solutions. This allows for the uniform maintenance of excellent polymerization inhibition suppression and polymerization inhibitor regeneration effects throughout a polymerization system in which monomer solutions and lubricating compositions coexist.
[0060] In some embodiments, the content of the polymerization inhibitor accelerator, which includes hindered phenol compounds and hydroquinone compounds, may be about 1 to 20% by weight relative to the total weight of the base oil. Within this range, a sufficient regeneration effect of the polymerization inhibitor can be achieved, while preventing a decrease in solubility within the polymerization system.
[0061] In some embodiments, the content of the polymerization inhibitor accelerator may be about 1 to 10% by weight relative to the total weight of the base oil. For example, the content of the hindered phenol compound in the polymerization inhibitor accelerator may be about 1 to 6% by weight relative to the total weight of the base oil. If the content of the hindered phenol compound exceeds, for example, about 6% by weight, oxidation of the base oil or lubricating composition may occur, causing discoloration of the oil.
[0062] In some embodiments, the amount of hindered phenol compound in the polymerization inhibitor accelerator may be greater than the amount of hydroquinone compound. In this case, a sufficient polymerization inhibitor regeneration effect can be easily achieved within the lubricating composition.
[0063] In some embodiments, the lubricating composition may further contain a polar non-aromatic compound. The polar non-aromatic compound can be provided as a diluent or corrosion inhibitor for the polymerization inhibitor accelerator (e.g., a hindered phenol compound) described above. Alternatively, the polar non-aromatic compound can provide an intermediate medium or intermediate pathway for the regeneration mechanism of the polymerization inhibitor.
[0064] According to exemplary embodiments, the polar non-aromatic compound may include a fatty acid (e.g., oleic acid) compound having 10 to 30 carbon atoms.
[0065] A polar non-aromatic compound is added together, and the regeneration cycle of the polymerization inhibitor (e.g., phenothiazine) can be repeated together with the aforementioned hindered phenol compound (e.g., BHT).
[0066] For example, a hydrogen atom bonded to the nitrogen atom of phenothiazine can be removed and transferred to a radicalized fatty acid, generating an activated phenothiazine radical. This activated phenothiazine radical can then accept a hydrogen atom from a hydroxyl group contained in a hindered phenol compound, regenerating it back into phenothiazine.
[0067] As the aforementioned cycle is repeated, the activity of the polymerization inhibitor can be repeatedly regenerated within the polymerization system. This allows even a small amount of polymerization inhibitor to exert its inhibitory effect on the self-polymerization of carboxylic acid monomers over a long period of time.
[0068] In one embodiment, the content of the polar non-aromatic compound may exceed 1% by weight relative to the total weight of the base oil. In this case, sufficient solubility of the hindered phenol compound is ensured, and the polymerization inhibitor regeneration cycle can be easily initiated. In one embodiment, the content of the polar non-aromatic compound may exceed 1% by weight and be 10% by weight or less, preferably 5% by weight or less.
[0069] <Method for producing copolymers> Figure 1 is a schematic process flowchart illustrating a method for producing an ethylene-carboxylic acid copolymer according to an exemplary embodiment.
[0070] Referring to Figure 1, the first monomer supply unit 10 can supply a first monomer containing a carboxylic acid monomer.
[0071] Carboxylic acid monomers may include unsaturated carboxylic acids capable of chain polymerization reactions. According to exemplary embodiments, (meth)acrylic acid or its ester (e.g., (meth)acrylate) can be used as the carboxylic acid monomer. In this application, (meth)acrylic acid is used as a term encompassing methacrylic acid and acrylic acid.
[0072] For example, a carboxylic acid monomer can be transmitted from a first monomer supply unit 10, such as a storage tank, to a discharge unit 30 via a first flow path 20.
[0073] For example, one or more additives such as polymerization initiators, reaction inhibitors, and antioxidants can also be supplied together.
[0074] For example, known initiators in the field of polymer polymerization can be used as polymerization initiators. For instance, peroxides or peroxy compounds, azobis compounds, etc., can be used as polymerization initiators.
[0075] The carboxylic acid monomer moves to the discharge section 30 and can be discharged through the discharge channel 40 for copolymerization with, for example, an ethylene polymerizable monomer.
[0076] The discharge section 30 may include, for example, a discharge device such as a pump or a compressor. According to an exemplary embodiment, the aforementioned lubricating composition can be injected into the discharge section 30.
[0077] For example, the discharge section 30 includes a piston and a cylinder structure such as a bushing that encloses the piston, and a lubricating composition according to an exemplary embodiment can be injected into the gap between the piston and the cylinder structure.
[0078] Within the gap, repeated friction between the piston and cylinder structure can cause localized temperature increases due to frictional heat. If this exceeds the autopolymerization temperature of the carboxylic acid monomer, selfpolymers such as polyacrylic acid (PAA) may form. In this case, the gap may become clogged, shortening the replacement or cleaning cycle of the discharge section 30, reducing process efficiency, and potentially degrading the yield of the desired copolymer.
[0079] However, the aforementioned lubricating compositions can significantly activate the regeneration mechanism of the polymerization inhibitor by using a hindered phenol / hydroquinone polymerization inhibitor accelerator together with a polymerization inhibitor such as phenothiazine.
[0080] This increases the usage cycle of the discharge unit 30, suppresses the formation of self-polymers such as PAA, and improves process reliability.
[0081] In some embodiments, the injection rate of the lubricating composition into the discharge section 30 may be 20 kg / hr or more, and can preferably be adjusted to a range of 25 to 130 kg / hr. Within this range, self-polymerization can be efficiently suppressed by uniform contact with the carboxylic acid monomer supplied to the discharge section 30.
[0082] The second monomer stored in the second monomer supply unit 50 moves through the second channel 55, comes into contact with the carboxylic acid monomer supplied through the discharge channel 40, and can be copolymerized in the reactor 60. According to an exemplary embodiment, the second monomer may include an ethylene polymerizable monomer.
[0083] When ethylene is used as the second monomer, copolymerization between the carboxylic acid monomer and ethylene proceeds in the reactor 60 to produce an ethylene-carboxylic acid copolymer (e.g., an EAA copolymer).
[0084] In some embodiments, the polymerization initiator described above may be introduced into the reactor 60 together with the polymerization initiator via the second channel 55 or another channel. In this case, the polymerization initiator can prevent the self-polymerization of the carboxylic acid monomer from being promoted first.
[0085] In some embodiments, a chain transfer agent can be introduced during the polymerization process, for example, through a second channel 55. The chain transfer agent allows for easy control of the molecular weight and molecular weight distribution of the polymer product to a desired range.
[0086] The chain transfer agent may include, for example, non-polar organic compounds such as isobutane and propyne, or polar organic compounds such as methyl ethyl ketone, isopropylaldehyde, and vinyl acetate.
[0087] The process conditions in the discharge section 30 and the reactor 60 can be adjusted to prevent self-polymerization of carboxylic acid monomers and to improve the copolymer production efficiency.
[0088] In some embodiments, the temperature at the discharge section 30 may be lower than the temperature inside the reactor 60. For example, the temperature at the discharge section 30 may be about 20 to 120°C, and the temperature inside the reactor 60 may be about 150 to 270°C.
[0089] In some embodiments, the pressures in the discharge section 30 and the reactor 60 may be in the range of 1100 to 2500 bar, preferably 1300 to 2300 bar. In one embodiment, the discharge pressure in the discharge section 30 may be greater than the copolymerization pressure in the reactor 60.
[0090] The following are specific experimental examples to aid in understanding the present invention. However, the examples and comparative examples included in these experimental examples are merely illustrative of the present invention and do not limit the scope of the attached claims. It will be obvious to those skilled in the art that various changes and modifications can be made to these examples within the scope of the present invention and the technical concept, and it is natural that these variations and modifications fall within the scope of the attached claims.
[0091] Experimental Example 1: Measurement of the Autopolymerization of Acrylic Acid In a 1 L reactor treated with a nitrogen atmosphere, acrylic acid (AA) (99% purity, manufactured by Sigma-Aldrich) and a lubricating composition were mixed in the quantities shown in Table 1, and then sealed. The reactor was heated to 120°C, and the presence or absence of self-polymerization (PAA) formation in the reactor was observed every 10 minutes. The experiment was stopped as soon as PAA was observed with the naked eye, and the polymerization time was recorded. The results of the polymerization time measurements are also shown in Table 1 below.
[0092] In Table 1, PTZ and MeHQ are expressed in ppm relative to the mineral oil in the lubricating composition, and BHT is expressed in weight percent relative to the mineral oil.
[0093] [Table 1]
[0094] As shown in Table 1, when PTZ was used alone as a polymerization inhibitor in the lubricating composition, an effective PAA formation inhibitory effect could not be easily obtained. Furthermore, when the amount of PTZ, which has radical activity and poses an environmental risk, was significantly increased, an effective polymerization inhibition time was secured, as in Comparative Example 6.
[0095] In contrast, when both BHT and MeHQ were used as polymerization inhibitors, the polymerization delay time increased sharply even with a small amount of PTZ.
[0096] On the other hand, the lubricating composition of Example 4 was prepared in the same manner as in Example 3, except that it contained 8% by weight of BHT. In the case of Example 4, a polymerization time similar to that of Example 3 was measured, but yellowing of the lubricating composition occurred.
[0097] Experimental Example 2: Evaluation of Autopolymerization with Diluents The time of acrylic acid self-polymerization was measured using samples of lubricating compositions containing mineral oil, PTZ, and a diluent, in a manner similar to that used in Experimental Example 1. A diluent from Sigma-Aldrich was used.
[0098] The measurement results are shown in Table 2 below.
[0099] [Table 2]
[0100] As shown in Table 2, in the case of diluents for glycol compounds or non-polar aromatic compounds such as xylene, the polymerization inhibition effect was not substantially achieved even when PTZ was included.
[0101] Referring to Samples 10-14, which used fatty acid-based polar non-aromatic compounds such as oleic acid as diluents, the polymerization inhibition time increased significantly when these compounds were included in the lubricating composition in amounts exceeding 1% by weight, along with PTZ. [Explanation of symbols]
[0102] 10: First monomer supply unit 20: First channel 30:Discharge part 40: Discharge channel 50: Second monomer supply unit 55: Second channel 60: Reactor
Claims
1. A lubricating composition used in an apparatus for producing copolymers using carboxylic acid monomers, Mineral oil as a base oil, A phenothiazine polymerization inhibitor represented by the following chemical formula 1, Polymerization inhibitors containing hindered phenol compounds and hydroquinone compounds, It contains fatty acids with 10 to 30 carbon atoms, The carboxylic acid monomer is (meth)acrylic acid or (meth)acrylate. The aforementioned hindered phenol compound is butylated hydroxytoluene (BHT), The hydroquinone compound is hydroquinone monomethyl ether (MeHQ), The content of the polymerization inhibitor is 1 ppm to 10 ppm relative to the weight of the mineral oil. The content of the polymerization inhibitor accelerator is 1% to 10% by weight relative to the weight of the mineral oil. The content of the hindered phenol compound is greater than the content of the hydroquinone compound. The content of the hindered phenol compound is 1% to 6% by weight relative to the weight of the mineral oil. A lubricating composition wherein the fatty acid content is greater than 1% by weight and 10% by weight or less relative to the weight of the mineral oil. 【Chemistry 1】 (In chemical formula 1, R １ ~R ８ (It is hydrogen.)
2. The steps include: injecting the lubricating composition described in claim 1 into the discharge section; The steps include: discharging a first monomer containing the carboxylic acid monomer through the discharging unit; A method for producing a copolymer, comprising the step of reacting the discharged first monomer with a second monomer.
3. The method for producing a copolymer according to claim 2, wherein the second monomer is an ethylene-based polymerizable monomer.
4. The method for producing a copolymer according to claim 2, wherein the injection rate of the lubricating composition into the discharge section is 25 to 130 kg / hr.
5. The method for producing a copolymer according to claim 2, wherein the temperature inside the discharge section is 20 to 120°C, and the discharge pressure from the discharge section is 1100 to 2500 bar.