Sulfur-free dispersant polymers for industrial applications

Abstract

The present invention relates to lubricants containing small amounts of dispersant polymers and their use to avoid particle formation and deposits in industrial machinery and equipment.

Description

[Technical Field]

[0001] The present invention relates to lubricants containing small amounts of dispersant polymers and their use to avoid particle formation and deposits in industrial machinery and equipment.

[0002] The present invention relates to the preparation of alkyl (meth)acrylate copolymers useful in industrial lubricant applications that are more resistant to aging. Lubricant and oil formulations oxidize and darken during use due to prolonged exposure to high temperatures and oxygen. If the oil becomes more susceptible to this aging process, the useful life of the oil formulation is significantly reduced, thereby necessitating more frequent maintenance and increasing equipment costs. The aging process not only darkens the oil, but also forms oxidation by-products that can accumulate and cause undesirable sludge or varnish that can damage machine parts. The use of polymer additives that tend to cause sludge or varnish requires shorter maintenance intervals and oil changes, thereby increasing costs for users. The ability to extend maintenance intervals is sometimes valuable to consumers and a common industry demand.

[0003] The object of the present invention was to provide an additive for industrial oil formulations, preferably compressor oils, turbine oils, hydraulic oils or gear oils, more preferably compressor oils, which is capable of dispersing particles resulting from, for example, oil aging during use of the equipment, keeping them dispersed in the oil, avoiding particle separation and avoiding the formation of sludge, gums and lacquers.

[0004] A typical compressor belongs to the group of rotary or reciprocating machines. They compress various gases, such as air, carbon dioxide, other chemical gases, or other refrigerants. Small refrigeration compressors are used in domestic refrigerators, while larger compressors are used, for example, to cool warehouses.

[0005] Additives are well known in the lubricant industry to be able to provide performance benefits such as wear and corrosion protection, improved oxidation stability, or to solve sealing problems.

[0006] Commonly used are polyalkyl(meth)acrylates, which are well-known additives used in a variety of applications such as engine oils, transmission oils, gear oils, hydraulic oils, shock absorber oils, and greases.

[0007] The use of dispersant polyalkyl(meth)acrylates as additives in compressor oils to avoid particle formation and deposits has not been reported previously.

[0008] WO 2022 / 139687 relates to a soot dispersant comprising an AB block copolymer, where the A block is a soot fixing unit and comprises an N-dispersant monomer and styrene or benzyl methacrylate.

[0009] US Patent Application Publication No. 2006 / 0189490 relates to lubricating oil compositions containing friction modifying additives, such friction modifying additives being block copolymers.

[0010] EP 4015604 relates to acrylate-olefin copolymers and their use as lubricant additives or synthetic base fluids.

[0011] Surprisingly, it has been discovered that low-molecular-weight alkyl (meth)acrylate copolymers containing less than 50 ppm sulfur (so-called sulfur-free alkyl (meth)acrylate copolymers) and at least 1,000 ppm nitrogen make it possible to formulate fluids with better oxidative and corrosion stability. The purpose of the inventive polymers in the formulation is to disperse particles resulting from, for example, oil aging during equipment use and keep them dispersed in the oil, avoiding particle separation and the formation of sludge, gums, and lacquers. This property is improved without sulfur, and the inventive sulfur-free products also make it possible to meet the other requirements mentioned above.

[0012] MODE FOR CARRYING OUT THE INVENTION The first object of the present invention is a method for avoiding particle and deposit formation in industrial oil formulations, comprising: (i) (a) 41% by weight to 99% by weight, preferably 46% by weight to 99% by weight, more preferably 48.5% by weight to 99% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 10 wt%, preferably 1 wt% to 5 wt%, more preferably 2.5 wt% to 3.5 wt% of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate; (c) 0 wt% to 2 wt% methyl methacrylate; (d) 0 wt. % to 49 wt. % of an α-olefin containing C8 to C16 carbon atoms; A process for preparing a sulfur-free statistical alkyl (meth)acrylate copolymer comprising: the alkyl (meth)acrylate copolymer has a weight average molecular weight Mw of 5,000 g / mol to 50,000 g / mol; (ii) adding 0.05 wt. % to 1.0 wt. % of the sulfur-free alkyl (meth)acrylate copolymer prepared in step (i) to a base oil or base oil blend; (iii) optionally adding one or more further additives; (iv) applying the industrial oil formulation prepared in step (ii) or (iii) to a compressor, turbine, hydraulic machine, or industrial gear, preferably a compressor; The present invention relates to a method comprising:

[0013] The content of each component (a), (b), (c), and (d) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), (c), and (d) total 100% by weight.

[0014] A further object is to provide a sulfur-free alkyl (meth)acrylate copolymer comprising: (a) 88% by weight to 99% by weight, preferably 93% by weight to 99% by weight, more preferably 94.5% by weight to 97.5% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1% to 10% by weight, preferably 1% to 5% by weight, more preferably 2.5% to 3.5% by weight of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate, preferably an N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; The present invention relates to the method further mentioned above, including:

[0015] A further object is to provide a sulfur-free alkyl (meth)acrylate copolymer comprising: (a) 90% by weight to 99% by weight, preferably 95% by weight to 99% by weight, more preferably 96.5% by weight to 97.5% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1% to 10% by weight, preferably 1% to 5% by weight, more preferably 2.5% to 3.5% by weight of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate, preferably an N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; The present invention relates to the method further mentioned above, including:

[0016] The content of each component (a), (b), and (c) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0017] A further object is to provide a sulfur-free alkyl (meth)acrylate copolymer comprising: (a) 94.5% by weight to 97.5% by weight, preferably 96.5% by weight to 97.5% by weight, of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 2.5 wt% to 3.5 wt% N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate; Including, The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. w The method further relates to the method as mentioned above, comprising:

[0018] The content of each component (a), (b), and (c) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0019] In the context of the present invention, the term "sulfur-free" statistical alkyl (meth)acrylate copolymer means that the alkyl (meth)acrylate copolymer contains less than 300 ppm, preferably less than 100 ppm, more preferably less than 50 ppm of sulfur.

[0020] The weight average molecular weight M of the statistical alkyl (meth)acrylate copolymer according to the present invention w is preferably in the range of 10,000 g / mol to 30,000 g / mol, more preferably 15,000 g / mol to 30,000 g / mol.

[0021] M w is determined by size exclusion chromatography (SEC) using commercially available polymethyl methacrylate standards. Determination is performed by gel permeation chromatography using THF as the eluent.

[0022] The term "(meth)acrylate" refers to both esters of acrylic acid and esters of methacrylic acid. According to the present invention, methacrylates are preferred.

[0023] The C8-18 alkyl (meth)acrylates for use in accordance with the present invention are esters of (meth)acrylic acid and linear or branched alcohols having 8 to 18 carbon atoms. The term "C8-18 alkyl (meth)acrylate" encompasses individual (meth)acrylic acid esters having alcohols of a particular length, as well as mixtures of (meth)acrylic acid esters having alcohols of different lengths.

[0024] Suitable C8-18 alkyl (meth)acrylates include, for example, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, 2-propylheptyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate.

[0025] The C10-15 alkyl (meth)acrylates for use in accordance with the present invention are esters of (meth)acrylic acid and linear or branched alcohols having 10 to 15 carbon atoms. The term "C10-15 alkyl (meth)acrylate" encompasses individual (meth)acrylic acid esters having alcohols of a particular length, as well as mixtures of (meth)acrylic acid esters having alcohols of different lengths.

[0026] Suitable C10-15 alkyl (meth)acrylates include, for example, decyl (meth)acrylate, isodecyl (meth)acrylate, 2-propylheptyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, and pentadecyl (meth)acrylate.

[0027] Preferably, at least 30% by weight of the C10-15 alkyl (meth)acrylate is an ester of (meth)acrylic acid and a branched alcohol having 10 to 15 carbon atoms.

[0028] N-disperse monomers for use in accordance with the present invention are selected from the group consisting of N,N-dimethylaminoethyl methacrylate (DMAEMA), N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), and N-vinylpyrrolidinone (NVP); preferred is N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm).

[0029] Hydroxy-substituted C2-4 alkyl (meth)acrylates for use in accordance with the present invention are selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate; preferred is 2-hydroxyethyl methacrylate (HEMA).

[0030] A further object is to provide a sulfur-free alkyl (meth)acrylate copolymer comprising: Polymer 1 consisting of 97% by weight of a mixture of C12-C15-alkyl methacrylates and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 2 consisting of 99% by weight of a mixture of C12-C15-alkyl methacrylates and 1% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 3 consisting of 95% by weight of a mixture of C12-C15-alkyl methacrylates and 5% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 4 consisting of 0.2% by weight of methyl methacrylate (MMA), 96.8% by weight of a mixture of C12-C15 alkyl methacrylates, and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm). is selected from the group consisting of The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 15,000 g / mol to 30,000 g / mol. w The method further relates to the method as mentioned above, comprising:

[0031] A further object is the method further mentioned above, wherein the sulfur-free alkyl (meth)acrylate copolymer is selected from the group consisting of:

[0032] Polymer 1, consisting of 97% by weight of a mixture of C12-C15-alkyl methacrylates and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 18,160 g / mol ± 20%, i.e., in the range of 27,240 g / mol to 24,970 g / mol.

[0033] Polymer 2, consisting of a mixture of 99% by weight of C12-C15-alkyl methacrylates and 1% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 25,520 g / mol ± 20%, i.e., in the range of 20,416 g / mol to 30,624 g / mol.

[0034] Polymer 3, consisting of a mixture of 95% by weight of C12-C15-alkyl methacrylate and 5% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 24,900 g / mol ± 20%, i.e. in the range of 19,920 g / mol to 29,880 g / mol.

[0035] Polymer 4, consisting of 0.2% by weight of methyl methacrylate (MMA), 96.8% by weight of a mixture of C12-C15-alkyl methacrylates, and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), and having a weight average molecular weight Mw in the range of 22,300 g / mol ± 20%, i.e., in the range of 17,840 g / mol to 26,760 g / mol.

[0036] The second object of the present invention is to (A) 85% to 99.95% by weight of a base oil; (B) 0.05% by weight to 1.0% by weight, preferably 0.05% by weight to 0.5% by weight, more preferably 0.1% by weight to 0.5% by weight, (a) 41% by weight to 99% by weight, preferably 46% by weight to 99% by weight, more preferably 48.5% by weight to 99% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 10 wt%, preferably 1 wt% to 5 wt%, more preferably 2.5 wt% to 3.5 wt% of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate; (c) 0 wt% to 2 wt% methyl methacrylate; (d) 0 wt. % to 49 wt. % of an α-olefin containing C8 to C16 carbon atoms; a sulfur-free statistical alkyl (meth)acrylate copolymer comprising: a sulfur-free statistical alkyl (meth)acrylate copolymer having a weight average molecular weight Mw of 5,000 g / mol to 50,000 g / mol; (C) 0% to 15% by weight of one or more further additives; The present invention relates to an industrial oil formulation comprising:

[0037] The content of each component (A), (B), and (C) is based on the total composition of the industrial oil formulation. In certain embodiments, the percentages of components (A), (B), and (C) total 100% by weight.

[0038] The content of each component (a), (b), (c), and (d) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), (c), and (d) total 100% by weight.

[0039] A further second object of the present invention is to provide a method for producing a hydroxyl group-containing copolymer of the present invention, comprising the steps of: (a) 88% by weight to 99% by weight, preferably 93% by weight to 99% by weight, more preferably 94.5% by weight to 97.5% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 10 wt%, preferably 1 wt% to 5 wt%, more preferably 2.5 wt% to 3.5 wt% of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate, preferably an N-dispersed monomer, more preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate;

[0023] The present invention relates to an industrial oil formulation as further mentioned above, comprising:

[0040] A further second object of the present invention is to provide a method for producing a hydroxyl group-containing copolymer of the present invention, comprising the steps of: (a) 90% by weight to 99% by weight, preferably 95% by weight to 99% by weight, more preferably 96.5% by weight to 97.5% by weight of a C8-18 alkyl (meth)acrylate, preferably a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 10 wt%, preferably 1 wt% to 5 wt%, more preferably 2.5 wt% to 3.5 wt% of an N-dispersed monomer or a hydroxy-substituted C2-4 alkyl (meth)acrylate, preferably an N-dispersed monomer, more preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate;

[0023] The present invention relates to an industrial oil formulation as further mentioned above, comprising:

[0041] The content of each component (a), (b), and (c) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0042] A second object of the present invention is to (A) 85% to 99.95% by weight of a base oil; (B) 0.05% by weight to 1.0% by weight, (a) 94.5% by weight to 97.5% by weight, preferably 96.5% by weight to 97.5% by weight, of a C10-15 alkyl (meth)acrylate; (b) 2.5 wt% to 3.5 wt% N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate; A sulfur-free statistical alkyl (meth)acrylate copolymer comprising: w a sulfur-free statistical alkyl (meth)acrylate copolymer having (C) 0% to 15% by weight of one or more further additives;

[0023] The present invention relates to an industrial oil formulation as further mentioned above, comprising:

[0043] The content of each component (A), (B), and (C) is based on the total composition of the industrial oil formulation. In certain embodiments, the percentages of components (A), (B), and (C) total 100% by weight.

[0044] The content of each component (a), (b), and (c) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0045] The third object of the present invention is to (a) 88% by weight to 99% by weight, preferably 90% by weight to 99% by weight, of a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 10 wt% of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; A sulfur-free statistical alkyl (meth)acrylate copolymer comprising: w The present invention relates to a sulfur-free statistical alkyl (meth)acrylate copolymer having the formula:

[0046] The content of each component (a), (b), and (c) is based on the total composition of the alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0047] A third object of the present invention is to (a) 93% by weight to 99% by weight, preferably 95% by weight to 99% by weight, of a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 5 wt% of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; A sulfur-free statistical alkyl (meth)acrylate copolymer comprising: w The present invention relates to a sulfur-free statistical alkyl (meth)acrylate copolymer having the formula:

[0048] The content of each component (a), (b), and (c) is based on the total composition of the statistical alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0049] A third object of the present invention is to (a) 94.5% by weight to 97.5% by weight, preferably 96.5% by weight to 97.5% by weight, of a C10-15 alkyl (meth)acrylate; (b) 2.5 wt% to 3.5 wt% of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; A sulfur-free statistical alkyl (meth)acrylate copolymer comprising: w The present invention relates to a sulfur-free statistical alkyl (meth)acrylate copolymer having the formula:

[0050] The content of each component (a), (b), and (c) is based on the total composition of the alkyl (meth)acrylate copolymer. In certain embodiments, the proportions of components (a), (b), and (c) total 100% by weight.

[0051] A third objective is to Polymer 1 consisting of 97% by weight of a mixture of C12-C15-alkyl methacrylates and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 2 consisting of 99% by weight of a mixture of C12-C15-alkyl methacrylates and 1% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 3 consisting of 95% by weight of a mixture of C12-C15-alkyl methacrylates and 5% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), Polymer 4 consisting of 0.2% by weight of methyl methacrylate (MMA), 96.8% by weight of a mixture of C12-C15 alkyl methacrylates, and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm). a sulfur-free statistical alkyl (meth)acrylate copolymer selected from the group consisting of: w The present invention relates to a sulfur-free statistical alkyl (meth)acrylate copolymer having the formula:

[0052] A further object relates to a sulfur-free statistical alkyl (meth)acrylate copolymer selected from the group consisting of:

[0053] Polymer 1, consisting of 97% by weight of a mixture of C12-C15-alkyl methacrylates and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 18,160 g / mol ± 20%, i.e., in the range of 27,240 g / mol to 24,970 g / mol.

[0054] Polymer 2, consisting of a mixture of 99% by weight of C12-C15-alkyl methacrylates and 1% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 25,520 g / mol ± 20%, i.e., in the range of 20,416 g / mol to 30,624 g / mol.

[0055] Polymer 3, consisting of a mixture of 95% by weight of C12-C15-alkyl methacrylate and 5% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), having a weight average molecular weight Mw in the range of 24,900 g / mol ± 20%, i.e. in the range of 19,920 g / mol to 29,880 g / mol.

[0056] Polymer 4, consisting of 0.2% by weight of methyl methacrylate (MMA), 96.8% by weight of a mixture of C12-C15-alkyl methacrylates, and 3% by weight of an N-dispersed monomer, preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), and having a weight average molecular weight Mw in the range of 22,300 g / mol ± 20%, i.e., in the range of 17,840 g / mol to 26,760 g / mol.

[0057] According to the present invention, the sulfur-free alkyl (meth)acrylate copolymer comprises at least (i) providing the monomer composition; (ii) initiating radical polymerization of the monomer composition; It is prepared by a method comprising:

[0058] The radical polymerization of the present invention can be carried out in the absence (Examples) or in the presence (Comparative Examples) of one or more of the above-mentioned sulfur-free chain transfer agents.

[0059] Standard free radical polymerization is described in detail, inter alia, in Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition. Generally, a polymerization initiator and optionally a chain transfer agent are used for this purpose.

[0060] To synthesize the alkyl (meth)acrylate copolymer, the above-mentioned monomer mixture can be polymerized by any known method. Free radical polymerization can be carried out using conventional radical initiators. These initiators are well known in the art. Non-limiting examples of these radical initiators include azo initiators such as 2,2'-azodiisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile), and 1,1-azo-biscyclohexanecarbonitrile; peroxide compounds such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert- butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-amylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, dicumene peroxide, 1,1 bis(tert-butylperoxy)cyclohexane, 1,1 bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, cumene hydroperoxide, and tert-butyl hydroperoxide.

[0061] The use of chain transfer agents can result in lower molecular weight poly(meth)acrylates, a technique widely known and practiced in the polymer industry and described in Odian, Principles of Polymerization, 1991.

[0062] Furthermore, novel polymerization techniques such as ATRP (atom transfer radical polymerization) and / or RAFT (reversible addition-fragmentation chain transfer) can be applied to obtain useful polymers derived from alkyl esters. These methods are well known. ATRP reaction methods are described, for example, in J.S. Wang et al., J. Am. Chem. Soc., Vol. 117, pp. 5614-5615 (1995), and Matyjaszewski, Macromolecules, Vol. 28, pp. 7901-7910 (1995). Furthermore, patent applications WO 96 / 30421, WO 97 / 47661, WO 97 / 18247, WO 98 / 40415, and WO 99 / 10387 disclose variations of the ATRP described above and are expressly incorporated by reference for purposes of this disclosure. The RAFT method is broadly presented, for example, in WO 98 / 01478, which is expressly incorporated by reference for purposes of this disclosure.

[0063] The polymerization can be carried out at normal pressure, reduced pressure, or elevated pressure. The polymerization temperature ranges from -20 to 200°C, preferably from 60 to 120°C, but no limitation is intended. The polymerization can be carried out with or without a solvent. The term solvent should be understood broadly here. According to a preferred embodiment, the polymer can be obtained by polymerization in a mineral oil of API Group I, II, or III, or a synthetic oil of API Group IV.

[0064] According to the present invention, the polyalkyl(meth)acrylate copolymer is preferably prepared without using a sulfur-containing chain transfer agent. However, if a sulfur-containing CTA such as n-dodecyl mercaptan or 2-mercaptoethanol is used in the radical polymerization of the monomer composition, its content should be less than 0.05 wt % based on the total weight of the monomer composition.

[0065] Preferably, to obtain the sulfur-free polyalkyl(meth)acrylate of the present invention, no sulfur-containing chain transfer agent is included in the monomer composition of the present invention or is not used or added in the radical polymerization of the monomer composition.

[0066] The recovered copolymer is a statistical copolymer.

[0067] Base oils used in industrial oil formulations include oils of lubricating viscosity, including natural and synthetic oils, oils derived from hydrocracking, hydrogenation and hydrofinishing, unrefined oils, refined oils, rerefined oils or mixtures thereof.

[0068] Base oils 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, Section 1.3, Subheading 1.3, "Base Stock Categories").

[0069] API currently defines five groups of lubricant materials (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 is polyalphaolefins, and Group V is everything else, including ester oils, for example. The table below shows these API classifications: [Table 1]

[0070] The kinematic viscosity (KV) at 100°C of suitable base oils used to prepare industrial oil formulations 100 ) is preferably 0.7 mm when determined in accordance with ASTM D445 2 / s~20mm 2 / s range, more preferably 2 mm 2 / s~10mm 2 / s range.

[0071] Particularly preferred industrial oil formulations of the present invention comprise at least one base oil selected from the group consisting of API Group II oils, API Group III oils, API Group IV oils, and mixtures thereof.

[0072] Further base oils that can be used in accordance with the present invention are Group II-III Fischer-Tropsch derived base oils.

[0073] 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 a synthetic product of the Fischer-Tropsch process. Fischer-Tropsch derived base oils are sometimes referred to as GTL (Gas-To-Liquids) base oils. Suitable Fischer-Tropsch derived base oils that can be advantageously used as the base oil in the industrial oil formulations of the present invention are, for example, those disclosed in EP 0 776 959 A, EP 0 668 342 A, WO 97 / 21788, WO 00 / 15736, WO 00 / 14188, WO 00 / 14187, WO 00 / 14183, WO 00 / 14179, WO 00 / 08115, WO 99 / 41332, EP 1 029 029, WO 01 / 18156, WO 01 / 57166 and WO 2013 / 189951.

[0074] The industrial oil formulations used in accordance with the present invention may also contain one or more further additives selected from the group consisting of pour point depressants, dispersants, antifoam agents, detergents, demulsifiers, antioxidants, antiwear additives, extreme pressure additives, friction modifiers, anticorrosion additives, metal deactivators, and metal passivators, and mixtures thereof; preferably antiwear additives, anticorrosion additives, and antioxidants.

[0075] The industrial oil formulations used in accordance with the present invention may preferably contain up to 2.5 wt. %, preferably 0.5 wt. % to 1.5 wt. %, of a performance package containing at least antiwear agents, anticorrosion agents, and antioxidants.

[0076] The performance package is preferably a zinc-free performance package, and more preferably is completely ashless.

[0077] Preferred pour point depressants are selected from the group consisting of, for example, alkylated naphthalene and phenol polymers, polyalkyl methacrylates other than those of the present invention, maleic acid copolymer esters, and fumaric acid copolymer esters, which can be advantageously used as effective pour point depressants. Industrial oil formulations can contain 0.1 wt. % to 0.5 wt. % of pour point depressants. Preferably, 0.3 wt. % or less of pour point depressants is used.

[0078] Suitable dispersants include poly(isobutylene) derivatives, such as poly(isobutylene) succinimide (PIBSI), including borated PIBSI, and ethylene-propylene oligomers with N / O functionality. The industrial oil formulation may contain up to 5 wt. % of at least one dispersant, based on the total weight of the industrial oil formulation.

[0079] Suitable antifoaming agents include, for example, silicone oils, fluorosilicone oils, and fluoroalkyl ethers. The industrial oil formulation may contain 0.01% to 0.02% by weight of at least one antifoaming agent, based on the total weight of the industrial oil formulation.

[0080] Detergents include metal-containing compounds such as phenoxides; salicylates; thiophosphonates, especially thiopyrophosphonates, thiophosphonates, and phosphonates; sulfonates, and carbonates. These compounds may be used preferably in neutral or overbased form.

[0081] Preferred demulsifiers include alkylene oxide copolymers and (meth)acrylates containing polar functional groups.

[0082] Suitable antioxidants include, for example, phenols such as 2,6-di-tert-butylphenol (2,6-DTB), 2,6-di-tert-butyl-4-ethylphenol, butylhydroxytoluene (BHT), 2,6-di-tert-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-tert-butylphenol); aromatic amines, in particular alkylated diphenylamines, N-phenyl-1-naphthylamine (PNA), N,N′-di-phenyl-p-phenylenediamine, polymeric 2,2,4-trimethyldihydroquinone (TMQ); “OOS triesters” = reaction products of dithiophosphoric acids with activated double bonds from olefins, cyclopentadiene, norbornadiene, α-pinene, polybutene, acrylates, maleates (ashless on combustion); organophosphorus compounds such as triaryl and trialkyl phosphites; organocopper compounds, and overbased calcium and magnesium phenoxides and salicylates. The industrial oil formulation may contain from 0.05% to 5% by weight of at least one antioxidant, based on the total weight of the industrial oil formulation.

[0083] Preferred antiwear and extreme pressure additives include phosphorus compounds such as trialkyl phosphates, triaryl phosphates, e.g., tricresyl phosphate, amine-neutralized mono- and dialkyl phosphates, ethoxylated mono- and dialkyl phosphates, phosphites, phosphonates, or phosphines. The industrial oil formulation may contain 0.05 wt. % to 3 wt. % of at least one antiwear and extreme pressure additive, based on the total weight of the industrial oil formulation.

[0084] Examples of metal deactivators include triazoles, thiadiazoles, and salicylidenes, such as N,N'-disalicylidene-1,2-diaminopropane.

[0085] Rust inhibitors are widely used. Common chemicals are carboxylates such as succinic acid half esters, sulfonates, alkylamines, and phosphates, for example, amine-neutralized phosphate esters.

[0086] Friction modifiers used may include mechanically active compounds such as molybdenum disulfide, graphite (including fluorinated graphite), poly(trifluoroethylene), polyamides, polyimides; compounds that form adsorption layers such as long-chain carboxylic acids, fatty acid esters, ethers, alcohols, amines, amides, imides; compounds that form layers by tribochemical reaction such as saturated fatty acids, phosphate and thiophosphate esters, xanthates, sulfurized fatty acids; compounds that form polymeric layers such as ethoxylated dicarboxylic acid partial esters, dialkyl phthalates, methacrylates, unsaturated fatty acids, and sulfurized olefins.

[0087] The above-mentioned additives are described in detail, inter alia, in T. Mang, W. Dresel (eds.): "Lubricants and Lubrication", Wiley-VCH, Weinheim 2001; RM Mortier, ST Orszulik (eds.): "Chemistry and Technology of Lubricants".

[0088] The present invention is further illustrated by the following non-limiting examples and comparative examples. The following examples serve to further illustrate preferred embodiments according to the present invention, but are not intended to limit the present invention.

[0089] Experimental Department Abbreviation BV100 Bulk kinematic viscosity measured at 100°C according to ASTM D445 DMAPMAm N-(3-dimethylaminopropyl)methacrylamide KV100 Kinematic viscosity measured at 100°C according to ASTM D445 LIMA: A mixture of C12-C15 alkyl methacrylates (average carbon number = 13.4), 60% branched M n number average molecular weight M w Weight average molecular weight nDDM n-dodecyl mercaptan PDI Polydispersity index, molecular weight distribution calculated by the Mw / Mn ratio

[0090] Test Method molecular weight The alkyl (meth)acrylate copolymers according to the invention and comparative examples were characterized with respect to their molecular weight and PDI.

[0091] Molecular weights were determined by size exclusion chromatography (SEC) using commercially available polymethyl methacrylate (PMMA) standards. For polymers not containing N-disperse monomers (such as CE1), molecular weights were determined by gel permeation chromatography with THF as eluent (flow rate: 1 mL / min; injection volume: 100 μl) using the following conditions:

[0092] column: Five SDV columns 8 x 300 mm, each 8 x 50 mm (PSS, Mainz) One solvent peak separation column 8 x 100 mm (Shodex) Number Type Dimensions Serial number Precolumn SDV 10μ 8X50mm 91121224 1 SDV LXL 10μ 8X300mm 6013101 2 SDV LinL 10μ 8X300mm 6082302 3 SDV 100Å 10μ 8X300mm 0071401 4 SDV 100Å 10μ 8X300mm 0070508 5 KF-800D 8X100mm 2007012

[0093] device: Agilent 1100 Series Pump G1310A PSS SECcurity Inline-Degaser 409-0024 Agilent 1260 Series Autosampler G1329B Agilent 1260 Series UV Detector G1314B Agilent 1100 Series RI Detector G1362A Agilent 1100 Series Control Module G1323B Techlab Column Oven K-5

[0094] Oven: 35°C Eluent: tetrahydrofuran The eluent is continuously distilled and circulated by a pump. Flow rate: 1ml / min Injection volume: 100μl Detection: RI: Temperature 35℃ UV: Wavelength 239nm Delay volume: 0.175 ml (between UV and RI signals) Software: PSS WinGPC software Concentration of sample solution: 2g / L (Mw>10 6 :1g / L...0.5g / L) Standard: PMMA (e.g. PSS (Mainz) or Polymer Laboratories) Concentration standard solution: 1g / l (Mw>10 6 For 0.5g / l, Mw>2×10 6 (0.25g / l) (narrow distribution) Internal standard: 1,2-dichlorobenzene → 0.2μL~99.8μL sample

[0095] For polymers containing N-disperse monomers (such as Inventive Examples 1-4 and CE2-5), molecular weights were determined by gel permeation chromatography (flow rate: 1 mL / min; injection volume: 100 μl) with THF+0.02 Mol 2-(diethylamino)ethylamine as eluent using the following conditions:

[0096] column: Five SDV columns 8 x 300 mm, each 8 x 50 mm (PSS, Mainz) Number Type Dimensions Serial number Precolumn SDV 10 3 A 10μ 8X50mm 3051510 1 SDV 10 3 A 10μ 8X300mm 3051502 2 SDV 10 3 A 10μ 8X300mm 3051505 3 SDV 10 3 A 10μ 8X300mm 3051512 4 SDV 10 3 A 10μ 8X300mm 3051512

[0097] device: Agilent 1100 Series Pump G1312A PSS SECcurity Inline-Degaser 409-0024 Agilent 1100 Series Autosampler G131313A Agilent 1260 Series RI Detector G1362A Agilent 1200 Series Control Module G4208A PSS SECurity Column Oven TCC6000

[0098] Oven: 35°C Eluent: Tetrahydrofuran + 0.02Mol DEAEA (2-(diethylamino)ethylamine) Flow rate: 1ml / min Injection volume: 100μl Detection: RI: Temperature 35℃ UV: Wavelength 239nm Delay volume: 0.175 ml (between UV and RI signals) Software: PSS WinGPC software Concentration of sample solution: 2g / L (Mw>10 6 :1g / L…0.5g / L) Standard: PMMA (ReadyCal manufactured by PSS (Mainz)) Concentration standard solution: 1g / L(Mw>10 6 For 0.5g / L, Mw>2×10 6 (0.25g / L) (narrow distribution) Internal standard: 1,2-dichlorobenzene → 0.2 μL to 99.8 μL sample

[0099] Sulfur and nitrogen content Sulfur and nitrogen contents were calculated using the molecular formulas of the monomers and chain transfer agents used to synthesize the polymers and the masses of the components added, with values ​​rounded to the nearest 100 ppm.

[0100] viscosity The alkyl (meth)acrylate copolymers according to the invention and comparative examples were obtained as compositions in oil characterized for bulk kinematic viscosity at 100° C. according to ASTM D445.

[0101] To determine the thickening of the polymer products, the kinematic viscosity at 100°C (KV100) was measured for 25 wt% blends of the Examples in Group I oil. The Group I oil had a starting viscosity of 5.4 cSt at 100°C. The blends were prepared by blending 25 g of the Examples and 75 g of Group I oil at 80°C for 30 minutes. The KV100 was then measured according to ASTM D445.

[0102] Deposit test / aging test Aging tests were performed by blending 0.5 wt.% of the polymer into ISO 220 fluid. 10 g of the mixture was placed in a test tube and stored uncovered in a 150°C oven for 30 days. After 30 days, the fluid was removed and visually observed for color change. The observed fluid color / darkening was recorded, and the fluid was then passed through filter paper to check for sludge formation. The amount of sludge formed was recorded using a scale of no deposit, minimal deposit, moderate deposit, or extensive deposit.

[0103] Preparation of Example 1: 100 g of Shellsol A150 ND was placed in a 1 L four-neck round-bottom flask. In a separate beaker, 485 g of LIMA, 15 g of DMAPMAm, and 15 g of tert-butyl peroxy-2-ethylhexanoate were mixed to form a reaction mixture. The round-bottom flask containing 100 g of Shellsol A150 ND was heated to 115°C, mixed using a C stir bar, and inerted with nitrogen. Once the reactor reached the set temperature, the reaction mixture was fed into the reactor at a rate of 1.7 g / min. After the reaction mixture was completely added to the reactor, the reactor was held at 110°C for 60 minutes.

[0104] Because all of the monomers used as starting materials are mixed together before the polymerization begins, the recovered polymer is a statistical copolymer.

[0105] Examples 2, 3, and 4 were prepared in the same manner as Example 1, except that the weight ratios of the reactants were changed according to Table 1 below. [Table 2]

[0106] Preparation of Comparative Example 1: 485 g of LIMA, 15 g of DMAPMAm, and 2.75 g of nDDM were placed in a 1 L, four-neck, round-bottom flask. The reactor was heated to 120°C, mixed using a C stir bar, and inerted with nitrogen. Once the reactor reached the set temperature, 2.25 g of tert-butyl peroxy-2-ethylhexanoate was fed into the reactor using the following dosing profile: 0.15 g in the first 60 minutes, 0.3 g in the next 60 minutes, and 0.9 g in the next 60 minutes. The reaction was allowed to continue stirring for 1 hour, and then the final 0.9 g of initiator was fed into the reactor. The reactor was held at 110°C for 60 minutes.

[0107] Since all of the monomers used as starting materials are mixed together before the polymerization begins, the recovered copolymer is a statistical copolymer.

[0108] Comparative Examples 2 to 4 were prepared in the same manner as Comparative Example 1, except that the weight ratio of the reaction components was changed according to Table 2 below. [Table 3]

[0109] Examples 1-4 are in accordance with the present invention and are sulfur-free. They contain nitrogen in the range of 1600 ppm to 8200 ppm and were prepared in the absence of any sulfur-containing modifiers.

[0110] Comparative Examples 1-5 were prepared without nitrogen (CE1) and / or in the presence of the sulfur-containing modifier nDDM (CE2-CE5).

[0111] Sulfur and nitrogen values ​​were calculated based on raw material data.

[0112] Characterization data as molecular weight, PDI, bulk viscosity, and KV100 are summarized in Table 3 below. [Table 4]

[0113] The alkyl (meth)acrylate copolymers according to the present invention exhibit a weight average molecular weight in the range of 20,000 g / mol to 30,000 g / mol. Their bulk kinematic viscosity at 100°C is 190 mmHg. 2 / s~210mm 2 / s range, and the KV100 data is 12mm 2 / s~13mm 2 / s.

[0114] The aging test results are shown in Table 4 below. [Table 5]

[0115] Examples 1-3 demonstrate that oil aging can be significantly reduced using polymers containing less than 50 ppm sulfur and at least 1000 ppm nitrogen. Aging tests conducted with these polymers show no deposit formation after a 30-day aging cycle, and filter paper tests show no visible deposits.

[0116] Comparative Example 1 does not contain any nitrogen-containing monomers and although there is little deposit, the oil shows sensitivity to aging due to rapid discoloration.

[0117] Comparative Examples 2-5 contain varying amounts of sulfur and nitrogen and all show significant darkening of the fluid and numerous deposits formed.

[0118] Table 5 below also shows the aging of ISO VG 220 fluid in the absence of polymer additives. [Table 6]

[0119] The ISO VG 220 oil darkens rapidly to brown over a four week period, while the oil treated with Inventive Example 1 only darkens to a light amber color. The fluid treated with Comparative Example 2 darkens the most and also has visible sludge formed.

Claims

1. 1. A method for avoiding particle and deposit formation in an industrial oil formulation, comprising: (i) (a) 93% to 99% by weight, preferably 95% to 99% by weight, of a C10-15 alkyl (meth)acrylate; (b) 1% to 5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; 1. A process for preparing a sulfur-free statistical alkyl (meth)acrylate copolymer comprising: the alkyl (meth)acrylate copolymer has a weight average molecular weight Mw of 5,000 g / mol to 50,000 g / mol, preferably 10,000 g / mol to 30,000 g / mol, more preferably 15,000 g / mol to 30,000 g / mol; (ii) adding 0.05 wt. % to 1.0 wt. % of the sulfur-free alkyl (meth)acrylate copolymer prepared in step (i) to a base oil or base oil blend; (iii) optionally adding one or more further additives; (iv) applying the industrial oil formulation prepared in step (ii) or (iii) to a compressor, turbine, hydraulic machine, or industrial gear, preferably a compressor.

2. the sulfur-free statistical alkyl (meth)acrylate copolymer is (a) 94.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; Including, The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 2. The method of claim 1, comprising:

3. the sulfur-free statistical alkyl (meth)acrylate copolymer is (a) 96.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; Including, The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 2. The method of claim 1, comprising:

4. 4. The method of claim 1, 2, or 3, wherein the N-dispersed monomer is selected from the group consisting of N,N-dimethylaminoethyl methacrylate (DMAEMA), N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), and N-vinylpyrrolidinone (NVP); preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm).

5. 5. The method of claim 1, 2, 3, or 4, wherein at least 30% by weight of the C10-15 alkyl (meth)acrylate of component (a) is branched.

6. (A) 85% to 99.95% by weight of a base oil selected from the group consisting of API Group II, III, and IV oils and mixtures thereof; (B) 0.05% by weight to 1.0% by weight, preferably 0.05% by weight to 0.5% by weight, more preferably 0.1% by weight to 0.5% by weight, (a) 93% to 99% by weight, preferably 95% to 99% by weight, of a C10-15 alkyl (meth)acrylate; (b) 1% to 5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; 1. A sulfur-free statistical alkyl (meth)acrylate copolymer comprising: a sulfur-free statistical alkyl (meth)acrylate copolymer having a weight average molecular weight Mw of 5,000 g / mol to 50,000 g / mol, preferably 10,000 g / mol to 30,000 g / mol, more preferably 15,000 g / mol to 30,000 g / mol; (C) 0 wt. % to 15 wt. % of one or more further additives; 1. An industrial oil formulation comprising:

7. The statistical alkyl (meth)acrylate copolymer (B) is (a) 94.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of an N-dispersed monomer, more preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate; Including, The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 7. The industrial oil formulation of claim 6, having

8. The statistical alkyl (meth)acrylate copolymer (B) is (a) 96.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of an N-dispersed monomer, more preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm); (c) 0% to 2% by weight of methyl methacrylate; Including, The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 7. The industrial oil formulation of claim 6, having

9. 9. An industrial oil formulation according to claim 7 or 8, wherein said N-disperse monomer of component (b) is selected from the group consisting of N,N-dimethylaminoethyl methacrylate (DMAEMA), N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm), and N-vinylpyrrolidinone (NVP); preferably N-(3-(dimethylamino)propyl)-methacrylamide (DMAPMAm).

10. 10. The industrial oil formulation of claim 6, 7, 8 or 9, selected from compressor oils, turbine oils, hydraulic oils, and gear oils; preferably compressor oils.

11. (a) 93% to 99% by weight of a C10-15 alkyl (meth)acrylate; (b) 1% to 5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; a sulfur-free statistical alkyl(meth)acrylate copolymer comprising: ｗ A sulfur-free statistical alkyl (meth)acrylate copolymer having

12. (a) 95% to 99% by weight of a C10-15 alkyl (meth)acrylate; (b) 1 wt% to 5 wt% N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; 17. The sulfur-free statistical alkyl (meth)acrylate copolymer of claim 16, comprising:

13. 13. The sulfur-free statistical alkyl (meth)acrylate copolymer according to claim 11 or 12, wherein the N-dispersed monomer is selected from the group consisting of N,N-dimethylaminoethyl-methacrylate, N-(3-(dimethylamino)propyl)-methacrylamide, and N-vinylpyrrolidinone; preferably N-(3-(dimethylamino)propyl)-methacrylamide.

14. (a) 94.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; and a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 14. The sulfur-free statistical alkyl (meth)acrylate copolymer of claim 11, 12, or 13, having

15. (a) 96.5% to 97.5% by weight of a C10-15 alkyl (meth)acrylate; (b) 2.5% to 3.5% by weight of N-dispersed monomer; (c) 0% to 2% by weight of methyl methacrylate; and a weight average molecular weight M of 10,000 g / mol to 30,000 g / mol. ｗ 13. The sulfur-free statistical alkyl (meth)acrylate copolymer of claim 11 or 12, having the formula:

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