Process for Producing Polyalkyl (Meth)acrylate Polymers

Abstract

The present invention relates to a novel method for producing polyalkyl(meth)acrylate polymers with improved compositional distribution, which polymers provide better productivity, solubility and improved performance in lubricant compositions, particularly in engine oil formulations.

Description

[Technical field]

[0001] The present invention relates to a novel method for producing polyalkyl (meth)acrylate polymers having an improved compositional distribution, which polymers provide better productivity, solubility and improved performance in lubricant compositions, especially in engine oil formulations.

[0002] Lubricants play a key role in reducing vehicle fuel consumption, and there is a continuing demand for improvements in fuel economy performance.

[0003] Motor oil formulations are commonly defined by the SAE J300 standard (SAE=Society of Automotive Engineers), which classifies motor oils into SAE viscosity grades xW-y, where x=0, 5, 10, 15, 20, 35 and y=8, 12, 16, 20, 30, 40, 50, 60. This is done, for example, by kinematic viscosity KV (ASTM D445) and high temperature high shear viscosity HTHS (ASTM D4683, D4741 and D5471), parameters that are important for engine protection. Lubricant properties are typically improved by the addition of additives to the lubricating oil. Viscosity index (VI) improvers are commonly added to lubricants to improve their thickening efficiency and protect the engine. In the past decade, there has been a great deal of effort to improve lubricants for better fuel efficiency.

[0004] Polyalkyl(meth)acrylate-based polymers, and especially polyalkyl(meth)acrylates containing macromonomers, are commonly used as additives, especially as viscosity index improvers. They provide good viscosity characteristics, such as low KV, in engine oil formulations. 40 , H.T.H.S. 80 and HTHS 100 values ​​and results in good fuel economy.

[0005] Polyalkyl(meth)acrylate polymers typically contain short chain alkyl(meth)acrylates and long chain alkyl(meth)acrylates, the short chain alkyl(meth)acrylates being more polar and contributing to the viscosity properties of the resulting polymer, while the long chain alkyl(meth)acrylates are less polar and provide the oil solubility of the resulting polymer.

[0006] The composition of the polyalkyl(meth)acrylate must be balanced between polar and non-polar monomers, since increased polarity is usually accompanied by reduced solubility and undesirable changes in the viscosity performance of the polymer.

[0007] Adding many polar monomers, such as methyl (meth)acrylate (MMA), butyl (meth)acrylate (BMA) or styrene to polyalkyl (meth)acrylates, and in particular to polyalkyl (meth)acrylates containing macromonomers, poses technical challenges as the polarity of the polymer increases too much, causing changes in viscosity and generally making the polymer less soluble in oil. One typical approach to counter this increased polarity is to balance the polarity of the polymer by increasing the amount of less polar comonomers, such as long chain alkyl (meth)acrylates or macromonomers. Although the solubility of the polymer in oil can be improved in this way, the drawback of this approach is that the KV in oil increases. 40 , H.T.H.S. 80 , or HTHS 100 This means that, for example, increasing the amount of long chain alkyl (meth)acrylate results in an increased KV 40 , H.T.H.S. 80 and HTHS 100 , which in turn means reduced fuel efficiency.

[0008] Comb polymer technology in general and their use as viscosity index improvers are previously known (US 2008 / 0194443 and US 2010 / 0190671). The viscosity performance of polyalkyl(meth)acrylate-based comb polymers can be improved, for example, by introducing new monomers. It is already known in the art that a certain amount of macromonomers has a beneficial effect on fuel efficiency (US 2010 / 0190671), that the presence of alkyl acrylates improves NOACK volatility (WO 2018 / 041755), and that a certain amount of imide functionality has a beneficial effect on friction reduction (WO 2019 / 012031).

[0009] Another challenge, usually associated with reduced solubility and the polymer becoming too polar, is that the productivity of the polymer and especially its scalability in the plant may be hindered. Possible consequences are, for example, a huge increase in turbidity in the product, increased in-process viscosity, increased heat generation and / or the formation of insoluble deposits. Any of these drawbacks may prevent the production of such products or at least lead to economically unfavorable production methods, where continuous runs are not possible, leading to shorter production cycles with expensive and costly cleaning steps of the production vessel after each production batch.

[0010] It is therefore an object of the present invention to provide polyalkyl(meth)acrylates, the polarity of which is increased as much as possible to give good KV 40 , H.T.H.S. 80 and HTHS 100 It improves or maintains performance while at the same time providing good solubility, scalability and economical productivity.

[0011] It has surprisingly been found that a novel process for producing polyalkyl(meth)acrylates, in which amounts of different monomers are split into a heel and one or more feeds having different compositions and concentrations, results in a more balanced polymer composition, i.e., results in the formation of higher amounts of polymer having a composition closer to its average polymer composition throughout the polymerization process. This approach results in a product that simultaneously has improved solubility, reduced haze (a measure of the solubility of the polymer in a given base oil) and reduced deposit formation in the reactor, improved scalability and very good viscosity characteristics. These modified process conditions additionally enabled the synthesis of new polymer compositions with improved viscosity characteristics for fuel efficiency that were previously unmanufacturable (due to increased in-process viscosity) and exhibited unfavorable solubility in oil.

[0012] technical level All the methods known in the art for the preparation of polyalkyl(meth)acrylates are based on the reaction of mixtures containing their monomers in the ratio as desired for the resulting polymer(s). These mixtures are either reacted in a one-pot reaction after the addition of an initiator or they are split into a heel and a feed, both of which have exactly the same composition.

[0013] US 2008 / 0194443 and US 2010 / 0190671 disclose the synthesis of comb polymers, in which a mixture of all monomers is added to the device and diluted with base oil. The reaction mixture is then heated to the desired temperature and reacted, and several shots of initiator are added after a certain time interval. Splitting the monomers into different feeds with different monomer compositions and concentrations is not described.

[0014] US 2011 / 0306533 and US 2011 / 0319305 disclose a method for preparing comb polymers, in which an initial reaction mixture is prepared containing all of the monomers and a solvent oil. This initial reaction mixture is then divided into a heel (about one-fifth of the initial reaction mixture) and a feed (about four-fifths of the initial reaction mixture). The composition of the monomers in both the heel and the feed are the same, as are the concentrations of the monomers. After reaching the reaction temperature, several shots of initiator are added after a certain time interval. The division of the monomers into different feeds with different compositions and concentrations of monomers is not described.

[0015] WO 2014 / 170169 discloses a method for preparing comb polymers, in which an initial reaction mixture is prepared containing all of the monomers and a solvent oil. This initial reaction mixture is then split into a heel (about one third of the initial reaction mixture) and a feed (about two thirds of the initial reaction mixture). The composition of the monomers in both the heel and the feed are the same, as are the concentrations of the monomers. After reaching the reaction temperature, several shots of initiator are added after a certain time interval. Splitting the monomers into different feeds with different compositions and concentrations is not described.

[0016] WO 2019 / 012031 relates to comb polymers and describes a base polymer synthesis, in which an apparatus is charged with a mixture of 300 g of monomer and 200 g of solvent oil. This mixture is heated and an initiator is added. Subsequently, another mixture of 300 g of monomer and 200 g of solvent oil having the same composition and concentration as the initial mixture is added as a feed, as well as a further shot of initiator. Division of the monomer into different feeds with different compositions and concentrations of the monomer is not described.

[0017] WO 2018 / 114673 discloses a method for producing comb polymers, in which an initial reaction mixture of different monomers and solvent oil is produced. 50% of the mixture is charged into a beaker, and the other 50% of the initial mixture is fed during a time interval. The monomer composition and concentration are the same. Several shots of initiator are added after a time interval. Splitting of the monomer into different feeds with different compositions and concentrations is not described.

[0018] WO 2018 / 041755 discloses a method for producing comb polymers in which a heel is charged with an initial mixture of monomers and solvent oil, and a feed of monomers in solvent is added, the composition of the monomers in the heel and the feed is the same, but the concentrations of the heel and the feed are different.

[0019] Detailed Description of the Invention According to the literature, the monomers commonly used to prepare polyalkyl(meth)acrylate polymers do not differ significantly in terms of their Q,e-parameters (Q=reactivity, e=polarity), which means that a person skilled in the art would not have expected any difficulties in the copolymerization of different monomers with similar Q,e-parameters. Only for sterically hindered monomers, the kinetics cannot be easily predicted or calculated according to the descriptions of existing polymerization models.

[0020] Copolymerization parameters must be defined individually for each comonomer pair, and temperature, medium and initiator must also be considered, because they are parameters of relative reactivity only. In such systems where the copolymerization parameters of monomer A-monomer B pairs are significantly different, the polymer molecules synthesized first show a different composition from those polymerized later. Therefore, partial demi-sickening is a known phenomenon that occurs in such polymer mixtures. Copolymers with constant composition over time can then be obtained by adding the faster polymerizing monomer according to its conversion or by working under azeotropic conditions. In industrial copolymerization and production where many comonomers are applied, this becomes challenging. The Q,e-parameters allow the estimation of unknown copolymerization parameters. Similar e-values ​​lead to azeotropic polymers, whereas different e-values ​​lead to alternating copolymers. For some comonomers, especially sterically hindered monomers or those that cannot be copolymerized, it is difficult to predict their copolymerization.

[0021] In systems that contain macromonomers, the kinetics of all monomer pairs can be really complicated. Therefore, it was a surprising discovery for those skilled in the art that simply separating the polar monomer from the non-polar (=oil-soluble) monomer was enough to obtain a polymer with a uniform distribution and much better solubility and viscosity performance than that produced without separation. This approach is more efficient and easier to implement than checking the reactivity (in oil) as is usually suggested in the literature, and also considering the radical concentration throughout the reaction.

[0022] The novel method described can be applied to all free radical polymerizations operated in a feed mode in which at least one comonomer exhibits copolymerization kinetics that vary significantly from the kinetics of the other comonomer.

[0023] In principle, all kinds of polyalkyl(meth)acrylates can be prepared by the process according to the invention, containing monomers which differ in terms of polarity, reactivity and oil solubility.

[0024] A first subject of the present invention therefore relates to a method for the preparation of a polyalkyl(meth)acrylate polymer comprising one or more apolar monomers (a) and one or more polar monomers (b), said method comprising the following steps: (i) a monomer mixture comprising 115-125% of a target content of monomer (a) and 95%-100% of a target content of monomer (b); 1 wherein the mixture 1 The concentration of the monomer in the mixture is 30 to 40%; (ii) a monomer mixture comprising 115% to 125% of the target content of monomer (a) and 95% to 100% of the target content of monomer (b); 2 wherein the mixture 2 the concentration of the monomer in is 30 to 40%; and (iii) A monomer mixture containing 110-120% of the target content of only monomer (b). 3 wherein the mixture 3 The concentration of the monomer in is 2 to 6%. The monomer mixture comprises 1 comprises 38 to 45% of the total amount of monomers used in the process, 2 comprises 38 to 45% of the total amount of monomers used in the process, and the monomer mixture 3 The method is characterized in that the monomers contained in the copolymer contain 15 to 20% of the total amount of monomers used in the method.

[0025] By non-polar monomer (a) is understood a less reactive monomer having good oil solubility selected from the group consisting of polyolefinic macromonomers and other sterically hindered monomers. Preferred polyolefinic macromonomers are esters of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene.

[0026] Polar monomer (b) is C 1~30 It is understood that the more reactive monomers, which have only moderate or even poor oil solubility, are selected from the group consisting of alkyl (meth)acrylates, substituted and unsubstituted styrenes. Preferred polar monomers are methyl methacrylate, butyl methacrylate, C 12~14 Alkyl methacrylate and styrene.

[0027] A first further object relates to a method as further described above, wherein the polyalkyl(meth)acrylate polymer is (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% by weight to 80% by weight of C 1~4 Alkyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C 10~30 Alkyl (meth)acrylate, preferably C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% by weight to 10% by weight of styrene Includes.

[0028] A first further object relates to a method as further described above, wherein the polyalkyl(meth)acrylate polymer is (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% by weight to 80% by weight of C 1~4 Alkyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C 10~30 Alkyl (meth)acrylate, preferably C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% by weight to 1% by weight of styrene Includes.

[0029] A first further object relates to a method as further described above, wherein the polyalkyl(meth)acrylate polymer is (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% by weight to 80% by weight of C 1~4 Alkyl methacrylate; (b2) 10% by weight to 20% by weight of C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% by weight to 1% by weight of styrene Includes.

[0030] The content of each of the components (a), (b1), (b2) and (b3) is based on the total composition of the polyalkyl (meth)acrylate polymer. In a particular embodiment, the proportions of components (a), (b1), (b2) and (b3) add up to 100% by weight.

[0031] The weight average molecular weight of the polyalkyl (meth)acrylate polymer according to the present invention is preferably within the range of 100,000 to 1,000,000 g / mol, more preferably within the range of 400,000 to 800,000 g / mol. The number average molecular weight of the polyalkyl (meth)acrylate polymer according to the present invention is preferably within the range of 30,000 to 300,000 g / mol, more preferably within the range of 60,000 to 200,000 g / mol.

[0032] Preferably, the polyalkyl(meth)acrylate polymer according to the present invention has a polydispersity index (PDI) M in the range of 2 to 10, more preferably in the range of 4 to 7. w / M n has. M w and M nis determined by size exclusion chromatography (SEC) using commercially available polymethylmethacrylate standards. The determination is performed by gel permeation chromatography using THF as the eluent.

[0033] In the context of the present invention, a polyalkyl(meth)acrylate polymer comprises a first polymer, also called backbone or main chain, and a number of further polymers, called side chains, covalently bonded to the backbone. In this case, the backbone of the polyalkyl(meth)acrylate polymer is formed by the linked unsaturated groups of the listed (meth)acrylates. The ester groups of the (meth)acrylic acid esters, the phenyl groups of the styrene monomers and the substituents of further free radically polymerizable comonomers form the side chains of the comb polymer.

[0034] The term "(meth)acrylate" refers to both esters of acrylic acid and esters of methacrylic acid. Methacrylates are preferred over acrylates.

[0035] The polyolefinic macromonomer comprises at least one group derived from a polyolefin. Polyolefins are known in the art and can be obtained by polymerizing alkenes and / or alkadienes consisting of the elements carbon and hydrogen, for example C2-C10-alkenes, such as ethylene, propylene, n-butene, isobutene, norbornene, and / or C4-C10-alkadienes, such as butadiene, isoprene, norbornadiene. The repeating units derived from the polyolefinic macromonomer preferably comprise at least 70% by weight, more preferably at least 80% by weight, and most preferably at least 90% by weight, based on the weight of the repeating units derived from the polyolefinic macromonomer, of groups derived from alkenes and / or alkadienes. The polyolefinic groups may in particular be present in hydrogenated form. In addition to the groups derived from alkenes and / or alkadienes, the repeating units derived from the polyolefinic macromonomer may comprise further groups. These include minor proportions of copolymerizable monomers. These monomers are known per se and include, among other monomers, alkyl (meth)acrylates, styrene monomers, fumarates, maleates, vinyl esters and / or vinyl ethers. The proportion of these groups relative to the copolymerizable monomers is preferably at most 30% by weight, more preferably at most 15% by weight, based on the weight of the repeating units derived from the polyolefin-based macromonomer. Moreover, the repeating units derived from the polyolefin-based macromonomer may contain starting groups and / or end groups which serve for functionalization or which result from the preparation of the repeating units derived from the polyolefin-based macromonomer. The proportion of these starting groups and / or end groups is preferably at most 30% by weight, more preferably at most 15% by weight, based on the weight of the repeating units derived from the polyolefin-based macromonomer.

[0036] A preferred polyolefinic macromonomer is an ester of (meth)acrylic acid and hydroxylated hydrogenated polybutadiene.

[0037] The hydroxylated hydrogenated polybutadienes for use according to the invention have number-average molar masses M of 4000 to 6000 g / mol, preferably 4500 to 5000 g / mol. n Due to their high molar mass, said hydroxylated hydrogenated polybutadienes can also be referred to in the context of the present invention as macroalcohols.

[0038] The number average molar mass M n is determined by size exclusion chromatography using commercially available polybutadiene standards. The determination is carried out by gel permeation chromatography using THF as eluent according to DIN 55672-1.

[0039] Preferably, the hydroxylated hydrogenated polybutadiene has a hydrogenation level of at least 99%. An alternative measure of the hydrogenation level that can be determined for the copolymer of the present invention is the iodine value. The iodine value refers to the number of grams of iodine that can be added onto 100 g of copolymer. Preferably, the copolymer of the present invention has an iodine value of 5 g iodine or less per 100 g of copolymer. The iodine value is determined according to DIN 53241-1:1995-05 by the Wyss method.

[0040] A preferred hydroxylated hydrogenated polybutadiene can be obtained according to GB 2270317.

[0041] Preferred is monohydroxylated hydrogenated polybutadiene. More preferably, the hydroxylated hydrogenated polybutadiene is hydroxyethyl or hydroxypropyl terminated hydrogenated polybutadiene. Particularly preferred is hydroxypropyl terminated polybutadiene.

[0042] These monohydroxylated hydrogenated polybutadienes can be prepared by first converting butadiene monomer to polybutadiene by anionic polymerization. The polybutadiene monomer can then be reacted with ethylene oxide or propylene oxide to produce a hydroxy-functionalized polybutadiene. The hydroxylated polybutadiene can then be hydrogenated in the presence of a suitable transition metal catalyst.

[0043] The esters of (meth)acrylic acid and the hydroxylated hydrogenated polybutadienes for use according to the invention are also referred to in the context of the invention as macromonomers, owing to their high molar mass.

[0044] The macromonomers for use according to the invention can be prepared by transesterification of alkyl (meth)acrylates, the reaction of which with the hydroxylated hydrogenated polybutadiene described above forms the esters of the invention. It is preferred to use methyl (meth)acrylate or ethyl (meth)acrylate as starting material.

[0045] This transesterification is widely known. For example, it is possible to use heterogeneous catalyst systems for this purpose, such as lithium hydroxide / calcium oxide mixture (LiOH / CaO), pure lithium hydroxide (LiOH), lithium methoxide (LiOMe) or sodium methoxide (NaOMe), or homogeneous catalyst systems, such as isopropyl titanate (Ti(OiPr)4) or dioctyltin oxide (Sn(OCt)2O). The reaction is an equilibrium reaction. Therefore, the low molecular weight alcohol released is typically removed, for example by distillation.

[0046] Moreover, the macromonomers can be obtained by direct esterification techniques, for example from (meth)acrylic acid or (meth)acrylic anhydride, preferably under acid catalysis with p-toluenesulfonic acid or methanesulfonic acid, or from free methacrylic acid by the DCC method (dicyclohexylcarbodiimide).

[0047] Additionally, the hydroxylated hydrogenated polybutadiene can be converted to an ester by reaction with an acid chloride, such as (meth)acryloyl chloride.

[0048] Preferably, in the above detailed preparation of the esters of the invention, a polymerization inhibitor is used, such as 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl radical and / or hydroquinone monomethyl ether.

[0049] C for use according to the present invention 1~30 Alkyl (meth)acrylates are esters of (meth)acrylic acid and linear or branched alcohols having 1 to 30 carbon atoms. 1~30 "Alkyl methacrylate" includes individual (meth)acrylic acid esters with alcohols of specific length, as well as mixtures of (meth)acrylic acid esters with alcohols of different lengths. Suitable C 1~30Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, 2-butyloctyl (meth)acrylate, 2-hexyloctyl (meth)acrylate, and the like. t)acrylate, decyl (meth)acrylate, 2-butyldecyl (meth)acrylate, 2-hexyldecyl (meth)acrylate, 2-octyldecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, 2-hexyldodecyl (meth)acrylate, 2-octyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl ( (meth)acrylate, 2-decyltetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 5-isopropylheptadecyl (meth)acrylate, 4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, 3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate acrylate, 2-decyloctadecyl (meth)acrylate, 2-tetradecyloctadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, cetyl eicosyl (meth)acrylate, stearyl eicosyl (meth)acrylate, docosyl (meth)acrylate and / or eicosyl tetratriacontyl (meth)acrylate, 2-decyl-tetradecyl (meth)acrylate, 2-decyloctadecyl (meth)acrylate, 2-dodecyl-1-hexadecyl (meth)acrylate, 1,2-octyl-1-dodecyl (meth)acrylate, 2-tetradecyl octadecyl (meth)acrylate, 1,2-tetradecyl-octadecyl (meth)acrylate and 2-hexadecyl-eicosyl (meth)acrylate.

[0050] Suitable styrene monomers are selected from the group consisting of styrene, substituted styrenes having alkyl substituents in the side chain, such as α-methylstyrene and α-ethylstyrene, substituted styrenes having alkyl substituents on the ring, such as vinyltoluene and paramethylstyrene, halogenated styrenes, such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene; styrene is preferred.

[0051] C for use according to the present invention 1~4 -Alkyl (meth)acrylates are esters of (meth)acrylic acid with linear or branched alcohols having 1 to 4 carbon atoms. 1~4 "-alkyl (meth)acrylate" includes individual (meth)acrylic acid esters with alcohols of specific length, as well as mixtures of (meth)acrylic acid esters with alcohols of different lengths. Suitable C 1~4 -Alkyl (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate and tert-butyl (meth)acrylate. Particularly preferred C 1~4 -Alkyl (meth)acrylates are methyl (meth)acrylate and n-butyl (meth)acrylate; methyl methacrylate and n-butyl methacrylate are particularly preferred.

[0052] C for use according to the present invention 10~30 Alkyl (meth)acrylates are esters of (meth)acrylic acid and linear or branched alcohols having 10 to 30 carbon atoms. 10~30"Alkyl methacrylate" includes individual (meth)acrylic acid esters with alcohols of specific length, as well as mixtures of (meth)acrylic acid esters with alcohols of different lengths. Suitable C 10~30 Examples of alkyl (meth)acrylates include 2-butyloctyl (meth)acrylate, 2-hexyloctyl (meth)acrylate, decyl (meth)acrylate, 2-butyldecyl (meth)acrylate, 2-hexyldecyl (meth)acrylate, 2-octyldecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, and 2-hexyldodecyl (meth). ) acrylate, 2-octyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 5-isopropylheptadecyl (meth)acrylate Acrylate, 4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, 3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, 2-decyloctadecyl (meth)acrylate, 2-tetradecyloctadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, cetyl eicosyl (meth)acrylate, stearyl eicosyl (meth)acrylate, docosyl (meth)acrylate and / or eicosyltetratriacontyl (meth)acrylate, 2-decyl-tetradecyl (meth)acrylate, 2-decyloctadecyl (meth)acrylate, 2-dodecyl-1-hexadecyl (meth)acrylate, 1,2-octyl-1-dodecyl (meth)acrylate, 2-tetradecyloctadecyl (meth)acrylate, 1,2-tetradecyl-octadecyl (meth)acrylate and 2-hexadecyl-eicosyl (meth)acrylate.

[0053] C for use according to the present invention 10~15 Alkyl methacrylates are esters of methacrylic acid with alcohols having 10 to 15 carbon atoms. 10~15 "Alkyl methacrylate" includes individual methacrylic acid esters with alcohols of specific lengths, as well as mixtures of methacrylic acid esters with alcohols of different lengths. Suitable C 10~15 Alkyl methacrylates include, for example, decyl methacrylate, undecyl methacrylate, 5-methylundecyl methacrylate, dodecyl methacrylate, 2-methyldodecyl methacrylate, tridecyl methacrylate, 5-methyltridecyl methacrylate, tetradecyl methacrylate, and / or pentadecyl methacrylate.

[0054] Particularly preferred C 10~15 Alkyl methacrylate is a linear C 12~14 Methacrylic acid esters of alcohol mixtures (C 12~14 alkyl methacrylate).

[0055] The method according to the invention is a free radical polymerization. Conventional free radical polymerization is described, inter alia, in Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition. Generally, a polymerization initiator and a chain transfer agent are used for this. In the method according to the invention, the use of a chain transfer agent is not necessary.

[0056] According to the present invention, the initiator 1 is added to the monomer mixtures 1, 2 and 3 in an amount of 0.1% to 0.5% by weight, preferably 0.1% to 0.3% by weight, based on the total amount of monomers used in the reaction. An additional amount of initiator of 0.05% to 0.15% by weight, based on the total amount of monomers, 2 can optionally be added at the end of the reaction.

[0057] Initiator1 and 2 may be the same or different and include azo initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN) and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxides, tert-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate ... and bis(4-tert-butylcyclohexyl)peroxydicarbonate, tert-butylperoxyisopropyl carbonate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, and bis(4-tert-butylcyclohexyl)peroxydicarbonate.

[0058] Preferably, the initiator 1 and 2 is independently selected from the group consisting of 2,2'-azobis(2-methylbutyronitrile), tert-butylperoxy-2-ethylhexanoate, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, and tert-butylperoxy-3,5,5-trimethylhexanoate. Particularly preferably, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane is used as the initiator. 1 and tert-butyl peroxy 2-ethylhexanoate is the initiator 2 It is used as.

[0059] The polymerization may be carried out at normal, reduced or elevated pressure. The polymerization temperature is generally in the range of 20°C to 200°C, preferably 90°C to 100°C.

[0060] The polymerization is carried out using a solvent. The term solvent should be understood in a broad sense here. The solvent is selected according to the polarity of the monomers used, and it is preferred to use API Group III oils, relatively light diesel oils and / or aromatic hydrocarbons, such as toluene or xylene.

[0061] The polymerization is carried out under a nitrogen atmosphere in a suitable reaction vessel equipped with an agitator and a temperature control system.

[0062] Base oils that may be used in the present invention include oils of lubricating viscosity, including natural and synthetic oils, oils derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined oils, refined oils, reclaimed oils, or mixtures thereof.

[0063] The base oil may also be defined as specified by the American Petroleum Institute (API) (see Appendix E-API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils, April 2008 Edition, Section 1.3, Subheading 1.3. "Base Stock Categories").

[0064] API currently defines five groups of lubricant base stocks (API 1509, Annex E - API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils, September 2011). Groups I, II, and III are mineral oils classified by the amount of saturates and sulfur they contain and their viscosity index; Group IV are polyalphaolefins; and Group V is everything else, including, for example, ester oils. The following table explains these API classifications: [Table 1]

[0065] The kinematic viscosity (KV) at 100° C. of a suitable non-polar base oil used to prepare the additive composition or lubricating composition according to the present invention 100 ) is preferably 3 mm in accordance with ASTM D445 2 / s~10mm 2 / s, more preferably within 4 mm 2 / s~8mm 2 / s range.

[0066] Further base oils that can be used in accordance with the present invention are Group II-III Fischer-Tropsch derived base oils. Fischer-Tropsch derived base oils are known in the art. The term "Fischer-Tropsch derived" means that the base oil is or is derived from the synthesis product of the Fischer-Tropsch process. Fischer-Tropsch derived base oils may also be referred to as GTL (gas to liquid) base oils. Suitable Fischer-Tropsch derived base oils which may advantageously be used as the base oil in the lubricating composition of the present invention are those described, for example, in European Patent Application Publication No. 0 776 959 (EP 0 776 959), European Patent Application Publication No. 0 668 342 (EP 0 668 342), WO 97 / 21788 (WO 97 / 21788), WO 00 / 15736 (WO 00 / 15736), WO 00 / 14188 (WO 00 / 14188), WO 00 / 14187 (WO 00 / 14187), WO 00 / 14183 (WO 00 / 14183), WO 00 / 14179 (WO 00 / 14179), International Publication No. WO 00 / 08115 (WO 00 / 08115), International Publication No. WO 99 / 41332 (WO 99 / 41332), European Patent Application Publication No. 1 029 029 (EP 1 029 029), International Publication No. WO 01 / 18156 (WO 01 / 18156), International Publication No. WO 01 / 57166 (WO 01 / 57166) and International Publication No. WO 2013 / 189951 (WO 2013 / 189951).

[0067] Particularly useful in the process according to the invention are base oils of API Group III, API Group V and mixtures thereof; preferred are mixtures of API Group III and API Group V base oils. As Group V base oils, dioctyl sebacate (DIOS) or Berylane are preferably used.

[0068] A further subject of the present invention therefore further relates to a method for producing a polyalkyl(meth)acrylate as outlined above, Blend 1 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 1; Blend 2 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 2; and Blend 3 contains 100 wt. % API Group III oil or mixtures thereof, based on the total amount of base oil used in Blend 3.

[0069] A further object of the present invention relates to a method for producing a polyalkyl(meth)acrylate polymer, the polyalkyl(meth)acrylate polymer being (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% by weight to 80% by weight of C 1~4 Alkyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C 10~30 Alkyl (meth)acrylate, preferably C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; The method comprises the steps of: (i) a monomer mixture comprising 115-125% of a target content of monomer (a) and 95%-100% of a target content of monomer (b); 1 wherein the mixture 1 The concentration of the monomer in the mixture is 30 to 40%; (ii) a monomer mixture comprising 115% to 125% of the target content of monomer (a) and 95% to 100% of the target content of monomer (b); 2 wherein the mixture 2 the concentration of the monomer in is 30 to 40%; and (iii) A monomer mixture containing 110-120% of the target content of only monomer (b). 3 wherein the mixture 2 The concentration of the monomer in is 2 to 6%. The monomer mixture comprises 1 comprises 38 to 45% of the total amount of monomers used in the process, 2 comprises 38 to 45% of the total amount of monomers used in the process, and the monomer mixture 3 comprises 15 to 20% of the total amount of monomers used in the method, Blend 1 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 1; Blend 2 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 2; and Blend 3 contains 100 wt. % API Group III oil or mixtures thereof, based on the total amount of base oil used in Blend 3.

[0070] A further object of the present invention relates to a method for producing a polyalkyl(meth)acrylate polymer, the polyalkyl(meth)acrylate polymer being (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% by weight to 80% by weight of C 1~4 Alkyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C 10~30 Alkyl (meth)acrylate, preferably C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; wherein the method comprises the steps of: (i) In the base oil, 1 a monomer mixture comprising 8 to 17% by weight of monomer (a), 70 to 75% by weight of monomer (b1), 12 to 17% by weight of monomer (b2), and 0 to 1% by weight of monomer (b3), based on the total amount of monomers in the monomer mixture. 1 wherein the mixture 1 the concentration of the monomer in is 30 to 40%; and (ii) In the base oil, 2 a monomer mixture comprising 8% by weight to 17% by weight of monomer (a), 70% by weight to 75% by weight of monomer (b1), 12% by weight to 17% by weight of monomer (b2), and 0% by weight to 1% by weight of monomer (b3), based on the total amount of monomers in the monomer mixture. 2 wherein the mixture 2 The concentration of the monomer in the mixture is 30 to 40%; (iii) In the base oil, 3 A monomer mixture comprising 81% by weight to 86% by weight of monomer (b1) and 15% by weight to 19% by weight of monomer (b2), based on the total amount of monomers in the monomer mixture. 3 wherein the mixture 3 The concentration of the monomer in is 2 to 6%. Monomer Mixture 1 comprises 38 to 45% of the total amount of monomers used in the process, 2 comprises 38 to 45% of the total amount of monomers used in the process, and the monomer mixture 3 comprises 15 to 20% of the total amount of monomers used in the method, Blend 1 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 1; Blend 2 comprises 65 wt.% to 75 wt.% of API Group III oil or mixtures thereof and 25 wt.% to 35 wt.% of Group V base oil or mixtures thereof, based on the total amount of base oils used in Blend 2; and Blend 3 contains 100 wt. % API Group III oil or mixtures thereof, based on the total amount of base oil used in Blend 3.

[0071] A further subject matter relates to a method as further described above, wherein the polyalkyl(meth)acrylate polymer is (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% by weight to 80% by weight of C 1~4 Alkyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C 10~30 Alkyl (meth)acrylate, preferably C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% by weight to 1% by weight of styrene Includes.

[0072] A first further object relates to a method as further described above, wherein the polyalkyl(meth)acrylate polymer is (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% by weight to 80% by weight of C 1~4 Alkyl methacrylate; (b2) 10% by weight to 20% by weight of C 10~15 Alkyl methacrylate, more preferably C 12~14 Alkyl methacrylate; and (b3) 0% to 1% by weight of styrene; Includes.

[0073] The content of each of the components (a), (b1), (b2) and (b3) is based on the total composition of the polyalkyl (meth)acrylate polymer. In a particular embodiment, the proportions of components (a), (b1), (b2) and (b3) add up to 100% by weight.

[0074] A second subject of the invention further relates to polyalkyl(meth)acrylates prepared by the process as outlined above.

[0075] The polymers produced by the process of the present invention have the advantage that they provide low KV of lubricating oil compositions containing them. 40 , H.T.H.S. 80 and HTHS 100 A given HTHS value (e.g. 2.6 mPas) 150 are characterized by their contribution to the Therefore, the polyalkyl(meth)acrylate polymers produced by the process of the present invention can be used in all conventional grades of motor oils having the viscosity characteristics defined in document SAE J300.

[0076] A third object of the present invention therefore relates to the use of the polyalkyl(meth)acrylate polymers produced by the process of the present invention for improving the kinematic viscosity and HTHS performance of lubricating oil compositions, in particular engine oil formulations.

[0077] A fourth object of the present invention relates to an additive composition comprising: (A1) 40 to 76% by weight, preferably 56% to 67% by weight, of API Group III oils and mixtures thereof; (A2) 4% to 20% by weight, preferably 8% to 14% by weight, of an API Group V oil or a mixture thereof; and (B) 20% to 40% by weight, preferably 25% to 30% by weight, of a polyalkyl(meth)acrylate polymer produced by the method as described herein above. Includes.

[0078] The content of each of the components (A1), (A2) and (B) is based on the total composition of the additive composition. In a particular embodiment, the proportions of components (A1), (A2) and (B) total 100% by weight.

[0079] Base oils that may be used in the additive composition further include oils of lubricating viscosity as described above.

[0080] A fifth object of the present invention relates to the use of an additive composition comprising at least one polyalkyl(meth)acrylate polymer produced by the process of the present invention and a base oil for improving the kinematic viscosity and HTHS performance of lubricating oil compositions, in particular engine oil formulations.

[0081] The invention is illustrated by the following non-limiting examples. EXAMPLES

[0082] Experimental section Abbreviations Group V Oil 2.3cSt KV from Total 40 Synthetic base oil having C 12~14 AMA C 12~14 -Alkyl methacrylate CCS Cold cranking stability HTHS 80 High temperature high shear viscosity at 80°C measured according to CEC L-036 HTHS 100 High temperature high shear viscosity at 100°C measured according to CEC L-036 HTHS 150 High temperature high shear viscosity at 150°C measured according to CEC L-036 KV Kinematic viscosity measured according to ASTM D445 KV 40 Kinematic viscosity at 40°C measured according to ISO 3104 KV 100 Kinematic viscosity at 100°C measured according to ISO 3104 LMA Lauryl methacrylate; MM Macromonomer MMA Methyl methacrylate M n number average molecular weight M w Weight average molecular weight NB 3020 Nexbase® 3020, 2.2 cSt KV from Neste 100 Group III base oil having NB 3043 Nexbase® 3043, 4.3 cSt KV from Neste 100 Group III base oil having Nexbase® 3080, 8cSt KV from Neste 100 Group III base oil having nBMA n-Butyl methacrylate OLOA 55516 DI package for PCMO commercially available from Oronite PAO4 4cSt KV 100 A polyalphaolefin base oil having PCMO Passenger Car Motor Oil PDI polydispersity index PPD Pour Point Depressant Sty Styrene VI Viscosity index, measured according to ISO 2909 VPL® 1-300 A pour point depressant commercially available from Evonik Yubase 4+ 4.2cSt KV from SK Lubricants 100 Group III base oils having

[0083] Test Method The polyalkyl(meth)acrylate polymers according to the invention and comparative examples were characterized with respect to their molecular weight and PDI.

[0084] The molecular weight was determined by size exclusion chromatography (SEC) using commercially available polymethylmethacrylate (PMMA) standards. The determination is carried out by gel permeation chromatography using THF as eluent (flow rate: 1 mL / min; injection volume: 100 μl).

[0085] The additive compositions containing the polyalkyl(meth)acrylate polymers according to the present invention and the comparative examples were evaluated for their viscosity index (VI) according to ASTM D 2270 at 40°C (KV 40 ) and 100℃(KV 100 ) according to ASTM D445 and for their solubility.

[0086] The lubricating oil compositions containing the comb polymers according to the present invention and the comparative examples were subjected to heating at 40°C (KV 40 ) and 100℃(KV 100 The compositions were characterized according to ASTM D445 for kinematic viscosity at 25° C., according to ASTM D 2270 for viscosity index (VI), according to CEC L-036 for high temperature high shear viscosity at 80° C., 100° C. and 150° C., and for their solubility.

[0087] To indicate the shear stability of the lubricating oil composition, the PSSI (Permanent Shear Stability Index) was calculated according to ASTM D 6022-01 (Standard Practice for Calculation of Permanent Shear Stability Index) based on data measured according to ASTM D 2603-B (Standard Test Method for Sonic Shear Stability of Polymer-Containing Oils, 12.5 minutes of ultrasonic treatment).

[0088] The solubility of the additive composition was tested in a 25% solution of polymer in Group III oil; the solubility of the lubricating oil composition was tested in a 3.75% solution of polymer in PAO4. The solution was analyzed by photometer after cooling to room temperature for at least one day, and the haze value was obtained using a Hunter LAB XE instrument and software. In measuring haze, the percentage of diffusely scattered light compared to the total transmitted light is reported. If the haze level is less than 5, the sample is considered to be completely clear to the eye and to show very good solubility in the lubricant formulation. At a haze level of 5 to 10, the sample is considered to be slightly hazy and the product is considered to show only moderate solubility in the lubricant formulation. At a haze level above 10, the sample is considered to be clearly hazy and the product is considered to have poor solubility in the lubricant formulation.

[0089] Synthesis of Hydroxylated Hydrogenated Polybutadiene. The produced macroalcohols have an average molar mass M n = 4750 g / mol.

[0090] The macroalcohol was synthesized by anionic polymerization of 1,3-butadiene with butyllithium at 20-45°C. Once the desired degree of polymerization was reached, the reaction was stopped by adding propylene oxide and the lithium was removed by precipitation with methanol. The polymer was subsequently hydrogenated in the presence of a noble metal catalyst under a hydrogen atmosphere up to 140°C and a pressure of 200 bar. After the hydrogenation was completed, the noble metal catalyst was removed and the organic solvent was extracted under reduced pressure. Finally, base oil NB 3020 was used for dilution to a polymer content of 70% by weight.

[0091] The vinyl content of the macroalcohol was 61%, the hydrogenation level was >99% and the OH functionality was >98%, these values ​​were determined by H-NMR (nuclear resonance spectroscopy).

[0092] Synthesis of macromonomers (MM) In a 2 L stirred apparatus equipped with a sabre stirrer, an air inlet tube, a thermocouple with a controller, a heating mantle, a column with a random packing of 3 mm wire spirals, a vapor distributor, a top thermometer, a reflux condenser and a cooling plate, 1000 g of the above macroalcohol are dissolved in 450 g of methyl methacrylate (MMA) by stirring at 60 ° C. 20 ppm of 2,2,6,6-tetramethylpiperidine-1-oxyl radical and 200 ppm of hydroquinone monomethyl ether are added to the solution. After heating to MMA reflux (bottom temperature about 110 ° C.) with air for stabilization, about 20 g of MMA are distilled off for azeotropic drying. After cooling to 95 ° C., 0.30 g of LiOCH3 are added and the mixture is heated back to reflux. After about 1 hour of reaction time, the top temperature has dropped to about 64 ° C. due to methanol formation. The methanol / MMA azeotrope formed is constantly distilled off until a constant head temperature of about 100° C. is again established. At this temperature, the mixture is reacted for another hour. Most of the MMA is drawn off under reduced pressure for further workup. Insoluble catalyst residues are removed by pressure filtration (Seitz T1000 depth filter). The content of NB 3020 "carried over" into the copolymer synthesis described further below is taken into account accordingly.

[0093] Synthesis of comb-shaped polymers Table 1: Net monomer composition of comb polymers produced according to the invention. [Table 2]

[0094] Polymer 1 (original method - comparative example): In an apparatus equipped with a four-neck flask and a precision glass stirrer, a monomer mixture having the following composition was added: 1(=heel) was charged: 15% macromonomer (70% in NB3020), 15.2% LMA, 69.4% nBMA, 0.2% styrene and 0.2% MMA based on the total amount of monomers. An oil mixture of NB3043 and Group V oil was added to reach a concentration of 40% monomer in oil. The resulting reaction mixture contained 60% oil mixture, including 4.3% by weight NB3020, 66.9% by weight NB3043 and 28.8% by weight Group V base oil based on the total amount of oil composition. After heating to 95° C. under nitrogen, 0.15% 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane based on the total amount of monomers was added and the temperature was maintained. Subsequently, a monomer mixture containing 15% macromonomer (70% in NB3020), 15.2% LMA, 69.4% nBMA, 0.2% styrene, and 0.2% MMA, based on the total amount of monomers in the oil mixture containing NB3043 and Group V oil, was used. 2 (=feed) and 0.2% by weight of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, based on the total amount of monomers present in the feed, were added at a constant metering rate within 3 hours. 2 contained 40% monomer and 60% oil mixture including 4.3% NB3020, 66.9% NB3043, and 28.8% Group V oil by weight based on the total weight of the oil composition. The resulting reaction mixture was further maintained at 96° C. for another 2 hours. Subsequently, another 0.2% of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane based on the total amount of monomers was added, and the resulting reaction mixture was diluted with NB3043 to 30% solids within 3 hours. The contained reaction mixture was then again maintained at 96° C. for another 2 hours, after which another 0.1% of tert-butylperoxy-2-ethyl-hexanoate based on the total amount of monomers was added, and the mixture was stirred at 95° C. overnight. The next day, the mixture was diluted with NB3043 to 25% polymer. After the mixture was cooled quickly it had a slightly inhomogeneous and gel-like appearance.

[0095] Table 2: Composition of the monomer mixture used to prepare polymer 1. [Table 3]

[0096] Polymer 2 (split feed method): In an apparatus equipped with a four-neck flask and a precision glass stirrer, a monomer mixture having the following composition was added: 1 (=heel) was charged: 18.1% macromonomer (70% in NB3020), 12.7% LMA, 58.8% nBMA, 0.2% styrene and 0.2% MMA based on the total weight of the monomer composition. An oil mixture of NB3043 and Group V oil was added to reach a concentration of 35.4% monomer in oil. The resulting reaction mixture contained 64.6% oil mixture, including 4.3% by weight NB3020, 66.9% by weight NB3043 and 28.8% by weight Group V oil based on the total weight of the oil composition. After heating to 96° C. under nitrogen, 0.15% 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane based on the total weight of monomer was added and the temperature was maintained. Subsequently, a monomer mixture containing 18.1% macromonomer (70% in NB3020), 12.7% LMA, 68.8% nBMA, 0.2% styrene, and 0.2% MMA, based on the total amount of monomers in the oil mixture containing NB3043 and Group V oil. 2 (=Feed 1) and 0.2% of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, based on the total amount of monomers, were added at a constant metering rate within 3 hours. 2 contained 35.4% monomer and 64.6% oil mixture including 4.3% NB3020, 66.9% NB3043, and 28.8% Group V oil by weight based on the total weight of the oil composition. Subsequently, a monomer mixture containing 15.6% LMA and 84.4% nBMA based on the total amount of monomers was 3(=Feed 2) and 0.2% of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane and NB3043 based on the total amount of monomers were added at a constant metering rate within 3 hours. 3 It contained 4.25% monomer and 95.75% NB3043. After the addition was completed, the reaction mixture showed 30% solids. The reaction was then again maintained at 96° C. for another 2 h, after which another 0.1% tert-butylperoxy-2-ethyl-hexanoate based on the total amount of monomer was added and the mixture was stirred overnight at 96° C. The next day, the mixture was diluted to 25% solids with NB3043.

[0097] Table 3: Composition of the monomer mixture used for the preparation of polymer 2. [Table 4]

[0098] Polymer 3 (split feed method): Polymer 3 was prepared following the protocol set forth for Polymer 2. The monomer mixture used is outlined in Table 4 below.

[0099] Table 4: Composition of the monomer mixture used to prepare polymer 3. [Table 5]

[0100] Polymer 4 (split feed method): Polymer 4 was prepared following the protocol set forth for Polymer 2. The monomer mixture used is outlined in Table 5 below.

[0101] Table 5: Composition of the monomer mixture used to prepare polymer 4. [Table 6]

[0102] Polymer 5 (split feed method): Polymer 5 was prepared following the protocol set forth for Polymer 2. The monomer mixture used is outlined in Table 6 below.

[0103] Table 6: Composition of the monomer mixture used to prepare polymer 5. [Table 7]

[0104] Table 7: Composition of the monomer mixture used to prepare polymer 6. [Table 8]

[0105] Polymer 7 (split feed method): Polymer 7 was prepared following the protocol set forth for Polymer 2. The monomer mixture used is outlined in Table 8 below.

[0106] Table 8: Composition of the monomer mixture used to prepare polymer 7. [Table 9]

[0107] Table 9: Net composition of comb polymers produced according to the invention. [Table 10]

[0108] Table 9 shows that using the split feed method of the present invention, the average content of the non-polar macromonomer could be reduced by 3.5% (from 12.9% in Polymer 1 to only 9.2% in Polymer 7) while the content of the polar monomer BMA could be increased by 3.5% (from 71.1% in Polymer 1 to 74.6% in Polymer 7).

[0109] Table 10: Properties of polymers 1-7. [Table 11]

[0110] Table 10 shows that the polymers obtained by the process according to the invention have high molecular weights ranging from 500000 to 700000 g / mol.

[0111] Table 11: KV of 4.9cSt 100 Viscosity of 3.75% polymers 1-7 in a Group III base oil blend (NB 3043 and NB 3080 from Neste). [Table 12]

[0112] According to Table 11, the viscosity measured at a polymer concentration of 15% is 7.7 to 8.9 mm. 2 / s KV 100 Value: 27.4~28.2mm 2 / s KV 40 The polymers exhibit extremely high viscosity index ranging from 272 to 323 and haze values. However, the haze value for polymer 1 resulting from the original synthesis method was above 10, and the polymer solutions appeared hazy. In contrast, the haze values ​​for solutions of polymers 2 to 7 ranged from 0.4 to 3.7 (clear appearance) to 5.5 to 6.6 (very slightly hazy appearance). This indicates that the polymers synthesized by the method described in this invention are significantly more soluble in oil. This indicates their wide applicability in oil formulations, such as engine oils, to improve fuel efficiency. It was not possible to prepare polymers 2-7 by using the method described for polymer 1. A slightly inhomogeneous and gel-like appearance was observed already after preparation of polymer 1. Together with the high haze value, this is an indication of the borderline solubility of the polymer in the base oil system used. For more polar monomer compositions as used in polymers 2-7 and applying the older method described in polymer 1, extremely high in-process viscosity and gelation of the monomer mixture during the polymerization was observed and the reaction had to be stopped before complete conversion of the monomers was obtained. Only by using the new polymerization method of polymers 2-7 were homogeneous polymers with low haze values ​​obtained at low in-process viscosity during the synthesis.

[0113] A problem that usually arises from the use of known methods is that the reaction mixtures used to produce commonly known polyalkyl(meth)acrylates contain monomers with different reactivity, leading to a polymer with a heterogeneous distribution of the non-polar and polar monomers. If one monomer is more reactive than the other second monomer, this monomer will be copolymerized in a higher amount at the beginning of the monomer feed, resulting in a polymer composition with an increased amount of this monomer at the beginning, while the second monomer will be enriched in the polymer formed during the later time in the feed process. The final product then contains a mixture of all the different fractions of the polymer composition formed during the entire process, from more polar fractions to less polar fractions compared to the average polymer composition. Typically, these are only very small deviations, but for polymerizations in which macromonomers are used, the deviations can be extremely large.

[0114] Thus, by using the split feed process of the present invention, it was possible to produce polymers with increased levels of polar monomers, especially BMA, and reduced levels of non-polar macromonomers that are still readily soluble in oil.

[0115] Evaluation of VI improvers in formulations KV of lubricating oil composition 40 and HTHS 100In order to demonstrate the effect of the polyalkyl(methacrylate) polymer according to the present invention on the performance, different formulation examples are prepared and the corresponding values ​​are measured. The formulations with Yubase 4+ as the base oil were prepared by using a formulation target of 0W20 according to SAE J300; i.e., HTHS of 2.6 mPas. 150 Towards this goal, the polymers produced according to the present invention were added to the formulation. The resulting polymer content was typically between 2 and 2.5 wt%. The characteristic EO formulation properties (KV 40 , K.V. 100 , H.T.H.S. 100 , H.T.H.S. 80 ) were measured and are summarized in Table 12 below.

[0116] Table 12: 0W20 engine oil formulations of polymers 1-7 with DI package in Yubase 4+ as base oil A, HTHS 150 Adjust to =2.6mPas. [Table 13-1] [Table 13-2]

[0117] A comparison of the formulation data presented in Table 12 shows that the fuel efficiency-related parameters HTHS 100 The HTHS was significantly improved from 4.83 (Polymer 1) to 4.49 (Polymer 7). 80 The value improved from 6.96 (Polymer 1) to 6.82 (Polymer 7), and the KV 40 A good low level of KV was maintained. 100 The levels were maintained at high levels well above engine oil specifications (J300; KV for 0W20 formulations). 100 ≧6.9mm 2 / s). The production of oil-soluble polymers of this composition and molecular weight was made possible by using a split feed method, while the conversion of the macromonomer over time was significantly improved. Parameters indicating good oil solubility are the appearance of the product and its haze value, which are improved by HTHS. 100 The values ​​were at very good levels for these new polymers. The process was improved by increasing the macromonomer conversion at the beginning of the reaction and increasing the BMA and LMA conversion at the end of the reaction. In this case, it was sufficient to increase the macromonomer concentration in the heel (and decrease its concentration in the feed) and at the same time decrease the BMA and LMA concentration in the heel (and increase its concentration in the feed) to achieve a more homogeneous reaction of the monomers.

[0118] In conclusion, the data presented above show that the process according to the invention for producing polyalkyl(meth)acrylates, in which the amounts of different monomers are split into a heel and one or more feeds having different compositions and concentrations, results in the formation of higher amounts of polymer having a composition closer to the average polymer composition throughout the polymerization process. This approach results in a product that simultaneously has reduced haze (an indicator of the solubility of the polymer in a given base oil), and therefore improved solubility of the polymer in lubricant formulations, especially engine oil formulations, improved scalability and very good viscosity properties.

Claims

1. 1. A method for producing a polyalkyl(meth)acrylate polymer, the polyalkyl(meth)acrylate polymer having a weight average molecular weight in the range of 100,000 to 1,000,000 g / mol and comprising the steps of: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of C １～４ Alkyl (meth)acrylate; (b2) 10% to 20% by weight of C １０～３０ Alkyl (meth)acrylate; and (b3) 0% to 10% by weight of styrene; based on the total amount of the polyalkyl (meth)acrylate polymer, The method comprises the steps of: (i) preparing a monomer mixture 1 comprising 115-125% of a target content of monomer (a) and 95%-100% of a target content of monomer (b), wherein the concentration of said monomers in mixture 1 is 30-40%; (ii) adding a monomer mixture 2 comprising 115-125% of the target content of monomer (a) and 95%-100% of the target content of monomer (b), where the concentration of said monomers in mixture 2 is 30-40%; and (iii) adding a monomer mixture 3 containing 110-120% of the target content of only monomer (b), where the concentration of said monomer in mixture 3 is 2-6%; The present invention includes The process characterized in that monomer mixture 1 comprises 38-45% of the total amount of monomers used in the process, monomer mixture 2 comprises 38-45% of the total amount of monomers used in the process, and monomer mixture 3 comprises 15-20% of the total amount of monomers used in the process.

2. The polyalkyl(meth)acrylate polymer may be selected from the group consisting of: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of C １～４ Alkyl (meth)acrylate; (b2) 10% to 20% by weight of C １０～３０ Alkyl (meth)acrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 1 , wherein the polyalkyl(meth)acrylate polymer comprises 3. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of a C 1-4 alkyl (meth)acrylate; (b2) 10% to 20% by weight of a C 10-15 alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; The method of claim 1 , wherein the polyalkyl(meth)acrylate polymer comprises 4. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of a C 1-4 alkyl (meth)acrylate; (b2) 10% to 20% by weight of a C 12-14 alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; The method of claim 1 , wherein the polyalkyl(meth)acrylate polymer comprises

5. The polyalkyl(meth)acrylate polymer may be selected from the group consisting of: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of C １～４ Alkyl methacrylate; (b2) 10% to 20% by weight of C １０～１５ Alkyl methacrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 1 , wherein the polyalkyl(meth)acrylate polymer comprises 6. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of a C 1-4 alkyl methacrylate; (b2) 10% to 20% by weight of a C 12-14 alkyl methacrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 1 , wherein the polyalkyl(meth)acrylate polymer comprises

7. 7. The method according to any one of claims 1 to 6, wherein the weight average molecular weight of the polyalkyl(meth)acrylate polymer is in the range of 400,000 to 800,000 g / mol.

8. 8. The method of claim 1, wherein the monomer mixture further comprises a base oil selected from the group consisting of API Group I, II, III, IV or V oils and mixtures thereof.

9. 9. The method of claim 1, wherein the monomer mixture further comprises a base oil comprising a mixture of API Group III and API Group V oils.

10. Blend 1 comprises 65 wt.% to 75 wt.% of an API Group III oil or a mixture thereof and 25 wt.% to 35 wt.% of a Group V base oil or a mixture thereof, based on the total amount of base oils used in Blend 1; Blend 2 comprises 65% to 75% by weight of an API Group III oil or a mixture thereof and 25% to 35% by weight of a Group V base oil or a mixture thereof, based on the total amount of base oils used in Blend 2; and 10. The method according to claim 1, wherein mixture 3 comprises 100% by weight of API Group III oil or a mixture thereof, based on the total amount of base oil used in mixture 3.

11. A polyalkyl(meth)acrylate polymer produced by the process of any one of claims 1 to 10.

12. 11. Use of a polyalkyl(meth)acrylate polymer produced by the process of any one of claims 1 to 10 to improve the kinematic viscosity and HTHS performance of a lubricating oil composition.

13. Use of a polyalkyl(meth)acrylate polymer produced by the method of any one of claims 1 to 10 to improve the kinematic viscosity and HTHS performance of an engine oil formulation.

14. 1. An additive composition comprising: (A1) 40 to 76 wt. % of API Group III oils or mixtures thereof; (A2) 4% to 20% by weight of an API Group V oil or a mixture thereof; and (B) 20% to 40% by weight of a polyalkyl(meth)acrylate polymer produced by the process according to any one of claims 1 to 10; based on the total weight of the additive composition.

15. The following: (A1) 56% to 67% by weight of an API Group III oil or a mixture thereof; (A2) 8% to 14% by weight of an API Group V oil or a mixture thereof; and (B) 25% to 30% by weight of a polyalkyl(meth)acrylate polymer produced by the process according to any one of claims 1 to 10; 15. The additive composition of claim 14, comprising, based on the total weight of the additive composition,

16. 10. A method for producing the polyalkyl(meth)acrylate polymer of claim 1, comprising the steps of: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of C １～４ Alkyl (meth)acrylate; (b2) 10% to 20% by weight of C １０～３０ Alkyl (meth)acrylate; and (b3) 0% to 10% by weight of styrene; based on the total amount of the polyalkyl (meth)acrylate polymer, The method comprises the steps of: (i) preparing a monomer mixture 1 in a base oil comprising 8% to 17% by weight of monomer (a), 70% to 75% by weight of monomer (b1), 12% to 17% by weight of monomer (b2) and 0% to 1% by weight of monomer (b3), based on the total amount of monomers in mixture 1, wherein the concentration of said monomers in mixture 1 is 30 to 40%; (ii) adding into the base oil a monomer mixture 2 comprising 8 wt.% to 17 wt.% of monomer (a), 70 wt.% to 75 wt.% of monomer (b1), 12 wt.% to 17 wt.% of monomer (b2) and 0 wt.% to 1 wt.% of monomer (b3), based on the total amount of monomers in mixture 2, where the concentration of the monomers in mixture 2 is 30-40%; and (iii) adding to the base oil a monomer mixture 3 comprising 81% to 86% by weight of monomer (b1) and 15 to 19% by weight of monomer (b2), based on the total amount of monomers in mixture 3, wherein the concentration of the monomers in mixture 3 is 2 to 6%; The present invention includes Monomer mixture 1 comprises 38-45% of the total amount of monomers used in the process, monomer mixture 2 comprises 38-45% of the total amount of monomers used in the process, and monomer mixture 3 comprises 15-20% of the total amount of monomers used in the process; Blend 1 comprises 65 wt.% to 75 wt.% of an API Group III oil or a mixture thereof and 25 wt.% to 35 wt.% of a Group V base oil or a mixture thereof, based on the total amount of base oils used in Blend 1; Blend 2 comprises 65 wt.% to 75 wt.% of an API Group III oil or a mixture thereof and 25 wt.% to 35 wt.% of a Group V base oil or a mixture thereof, based on the total amount of base oils used in Blend 2; and The process wherein Mixture 3 comprises 100 wt. % of an API Group III oil or mixtures thereof, based on the total amount of base oil used in Mixture 3.

17. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of a C 1-4 alkyl (meth)acrylate; (b2) 10% to 20% by weight of a C 10-15 alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; The method of claim 16, wherein the polyalkyl(meth)acrylate polymer comprises 18. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 25% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 60% to 80% by weight of a C 1-4 alkyl (meth)acrylate; (b2) 10% to 20% by weight of a C 12-14 alkyl methacrylate; and (b3) 0% to 10% by weight of styrene; The method of claim 16, wherein the polyalkyl(meth)acrylate polymer comprises

19. The polyalkyl(meth)acrylate polymer may be selected from the group consisting of: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of C １～４ Alkyl (meth)acrylate; (b2) 10% to 20% by weight of C １０～３０ Alkyl (meth)acrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 16, wherein the polyalkyl(meth)acrylate polymer comprises

20. The polyalkyl(meth)acrylate polymer may be selected from the group consisting of: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of C １～４ Alkyl methacrylate; (b2) 10% to 20% by weight of C １０～１５ Alkyl methacrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 16, wherein the polyalkyl(meth)acrylate polymer comprises 21. The polyalkyl(meth)acrylate polymer comprising: (a) 8 to 15% by weight of an ester of (meth)acrylic acid with hydroxylated hydrogenated polybutadiene; (b1) 70% to 80% by weight of a C 1-4 alkyl methacrylate; (b2) 10% to 20% by weight of a C 12-14 alkyl methacrylate; and (b3) 0% to 1% by weight of styrene; The method of claim 16, wherein the polyalkyl(meth)acrylate polymer comprises

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