LIPOPHYLIC COPOLYMERS COMPRISING POLAR MULTI-BLOCKS, PROCESS FOR THE PREPARATION THEREOF AND USE IN LUBRICATING COMPOSITIONS

Abstract

A lipophilic copolymer including polar multi-blocks having general formula (I):

[(B.sub.yA.sub.k).sub.s].sub.t(A.sub.jC.sub.m)  (I)

wherein: B represents at least one monomer unit deriving from a lipophilic monomer having general formula (II):

##STR00001## wherein: X represents a hydrogen atom; or a methyl group; R is selected from C.sub.1-C.sub.50 alkyl groups, linear or branched; A represents at least one monomer unit deriving from a polar monomer selected from: (a) compounds having general formula (III):

##STR00002## wherein X represents a hydrogen atom or a methyl group and n represents an integer comprised between 0 and 4; (b) (meth)acrylamide or (meth)acrylamides substituted on the nitrogen atom with one or two C.sub.1-C.sub.4 alkyl groups linear or branched; (c) di-(C.sub.1-C.sub.4)-alkylamino-(C.sub.1-C.sub.4)-alkyl (meth)acrylates; C represents at least one monomer unit deriving from a polar polyfunctional monomer having general formula (IV):

Z—(W).sub.p  (IV) wherein: Z represents a group containing carbon, hydrogen and, optionally, oxygen; and W represents a function able to react covalently with an alkyl radical.

Claims

1. A lipophilic copolymer comprising polar multi-blocks having general formula (I):
[(B.sub.yA.sub.k).sub.s].sub.t(A.sub.jC.sub.m)  (I) wherein: B represents at least one monomer unit deriving from a lipophilic monomer having general formula (II): ##STR00014## wherein: X represents a hydrogen atom; or a methyl group;  R is selected from C.sub.1-C.sub.50 alkyl groups, linear or branched; A represents at least one monomer unit deriving from a polar monomer selected from: (a) compounds having general formula (III): ##STR00015## wherein X represents a hydrogen atom or a methyl group and n represents an integer comprised between 0 and 4; (b) (meth)acrylamide or (meth)acrylamides substituted on the nitrogen atom with one or two C.sub.1-C.sub.4 alkyl groups, linear or branched, said alkyl groups optionally containing polar functional groups; (c) di-(C.sub.1-C.sub.4)-alkylamino-(C.sub.1-C.sub.4)-alkyl (meth)acrylates; C represents at least one monomer unit deriving from a polar polyfunctional monomer having general formula (IV):
Z—(W).sub.p  (IV) wherein: Z represents a group containing carbon, hydrogen and, optionally, oxygen; W represents a function able to react covalently with an alkyl radical; p is an integer or fractional number comprised between 2 and 8; y is an integer or fractional number comprised between 2 and 250; k is an integer or fractional number comprised between 0 and 90; j is an integer or fractional number comprised between 0 and 80; m is an integer or fractional number comprised between 0 and 10; s is an integer or fractional number comprised between 1 and 20; t is an integer or fractional number comprised between 3 and 20; provided that at least one between j and k is different from 0.

2. The lipophilic copolymer comprising polar multi-blocks according to claim 1, wherein in said general formula (I): B represents at least one monomer unit deriving from a lipophilic monomer having general formula (II) selected from the group consisting of: methyl methacrylate (X ═CH.sub.3 and R═CH.sub.3), medium-chain alkyl methacrylates (X═CH.sub.3 and R═C.sub.12H.sub.25—C.sub.15H.sub.31); long-chain alkyl methacrylates (X═CH.sub.3 and R═C.sub.16H.sub.33—C.sub.18H.sub.37), longer-chain alkyl methacrylates (X═CH.sub.3 and R═C.sub.18H.sub.37—C.sub.22H.sub.45); or mixtures thereof.

3. The lipophilic copolymer comprising polar multi-blocks according to claim 1, wherein in said general formula (I): A represents at least one monomer unit deriving from a polar monomer selected from the group consisting of: (a) compounds having general formula (III) selected from: acrylic acid (X═H and n=0), methacrylic acid (X═CH.sub.3 and n=0), hydroxyethyl acrylate (X═H and n=1), hydroxyethyl methacrylate (X═CH.sub.3, n=1); or mixtures thereof, (b) acrylamide, methacrylamide, N-iso-propyl-acrylamide, 2-hydroxy-propyl methacrylamide, N-[3-(dimethyl-amino)-propyl-methacrylamide, or mixtures thereof, (c) 2-(dimethyl-amino)-ethyl methacrylate, 2-(diethyl-amino)-ethyl methacrylate, 2-(dimethyl-amino)-ethyl acrylate, or mixtures thereof.

4. The lipophilic copolymer comprising polar multi-blocks according to claim 1, wherein in said general formula (I): C represents at least one monomer unit deriving from a polar polyfunctional monomer selected from the group consisting of: (a′) polyvalent methacrylic monomers having general formula (V) ##STR00016## wherein q+r=4, q>1, r<3, and X represents a hydrogen atom or a methyl group; (b′) polyethylene glycols di-(meth)acrylates having general formula (VI): ##STR00017## wherein n′ is an integer comprised between 1 and 10, and X represents a hydrogen atom or a methyl group; (c′) polyfunctional acrylamides having general formula (VII): ##STR00018## wherein t is an integer comprised between 1 and 4; (d′) calixarenes having general formula VIII): ##STR00019## wherein R′ represents a group having formula (VIIIa): ##STR00020## wherein X represents a hydrogen atom or a methyl group and R″ represents a hydrogen atom, or is selected from C.sub.1-C.sub.40 alkyl groups linear or branched, z is an integer comprised between 4 and 16; (e′) 2,2′-bis-[4-(methacryloxy-polyethoxy)-phenyl]-propanes having general formula (IX): ##STR00021## wherein u and v are an integer comprised between 1 and 10.

5. The lipophilic copolymer comprising polar multi-blocks according to claim 4, wherein in said general formula (I): C represents at least one monomer unit deriving from a polar polyfunctional monomer selected from the group consisting of: (a′) polyvalent methacrylic monomers having general formula (V) selected from: pentaerythritol tetra-acrylate (q=4; r=0), pentaerythritol tri-acrylate (q=3; r=1); (b′) polyethylene glycol di-(meth)acrylate [n=1 in the general formula (VI)]; (c′) N,N′-methylene-bis-acrylamide [t=1 in the general formula (VII)]; (d′) calixarenes having general formula (VIII) wherein R′ represents a group having formula (VIIIa): ##STR00022## wherein X represents a methyl group and R″ is selected from C.sub.8-C.sub.18 alkyl group, linear or branched, z is an integer comprised between 4 and 8; (e′) 2,2′-bis-[4-(methacryloxy-polyethoxy)-phenyl]-propane [u+v=10 in the general formula (IX)].

6. The lipophilic copolymer comprising polar multi-blocks according to claim 1, wherein in said general formula (I): B represents at least one monomer unit deriving from methyl methacrylate, at least one monomer unit deriving from dodecyl methacrylate and at least one monomer unit deriving from octadecyl methacrylate, with a random or block structure; A represents at least one monomer unit deriving from 2-hydroxymethyl methacrylate; C represents at least one monomer unit deriving from pentaerythritol tetra-acrylate, or at least one monomer unit deriving from N,N′-bis-methylene-bis-acrylamide; or at least one monomer unit deriving from 2,2′-bis[4-(methacryloxy-polyethoxy)-phenyl]-propane [u+v=10 in the general formula (IX)]; the values of y, k, j m, s and t, depending on the amount and type of monomers used, as well as the process used to obtain said lipophilic copolymer comprising polar multi-blocks having general formula (I), at least one between j and k being different from 0.

7. A process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 1, through RAFT-type copolymerization (“Reversible Addition Fragmentation Chain Transfer Polymerization”) comprising contacting, in the presence of at least one apolar organic solvent, the following compounds: (i) at least one lipophilic monomer having general formula (II); (ii) at least one polar monomer selected from: (a) compounds having general formula (III), (b) (meth)acrylamides optionally substituted on the nitrogen atom with one or two C.sub.1-C.sub.4 alkyl groups, linear or branched, (c) di-(C.sub.1-C.sub.4)-alkylamino-(C.sub.1-C.sub.4)-alkyl (meth)acrylates; (iii) at least one surfactant; (iv) optionally, at least one polar polyfunctional monomer selected from the group consisting of: (a′) polyvalent methacrylic monomers having general formula (V); (b′) polyethylene glycols di-(meth)acrylates having general formula (VI); (c′) polyfunctional acrylamides having general formula (VII); (d′) calixarenes having general formula (VIII); (e′) 2,2′-bis-[4-(methacryloxy-polyethoxy)-phenyl]-propanes having general formula (IX); (v) at least one chain transfer agent of the RAFT thiocarbonyl thio type (“Reversible Addition Fragmentation Chain Transfer Polymerization”); (vi) at least one radical polymerization initiator.

8. The process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 7, wherein: the apolar organic solvent is selected from the group consisting of: saturated aliphatic hydrocarbons having a number of carbon atoms greater than or equal to 7 such as heptane, octane; aromatic hydrocarbons such as toluene, xylene; lubricating base oils or mixtures thereof, it is selected from lubricating base oils or mixtures thereof, and/or said process is carried out in the presence of at least one lubricating base oil, said lubricating base oil being present at a concentration, expressed in weight percentage of lubricating base oil with respect to the total weight of the reaction mixture, comprised between 10% by weight and 90% by weight; and/or said lubricating base oil is selected from the group consisting of: lubricating base oils of mineral origin, of synthetic origin, of vegetable origin, of animal origin, or mixtures thereof, and/or in said process the lipophilic monomer (i) is used in an amount, expressed as a percentage by weight with respect to the total weight of the reaction mixture, comprised between 10% by weight and 90% by weight; and/or in said process the polar monomer (ii) is used in an amount, expressed as a percentage by weight with respect to the total weight of the reaction mixture, comprised between 0.5% by weight and 15% by weight; and/or in said process the surfactant (iii) is selected from the group consisting of: non-ionic surfactants such as surfactants containing polyethoxylated hydrophilic chains linked to a hydrocarbon group; surfactants containing block copolymers polyethylene oxide-polypropylene oxide; surfactants containing alkyl esters of sorbitan; ionic surfactants containing calcium or sodium alkyl benzene sulphonates; and/or in said process the surfactant (iii) is used in an amount, expressed as a percentage by weight with respect to the total weight of the reaction mixture, comprised between 0.2% by weight and 10% by weight; and/or in said process the polar polyfunctional monomer (iv) is used in an amount, expressed as a percentage by weight with respect to the total weight of the reaction mixture, comprised between 0.1% by weight and 5% by weight; and/or in said process the radical polymerization initiator (vi) is selected from the group consisting of: azo compounds such as 2,2′ azobis(iso-butyronitrile) (AIBN), 2,2′-azobis(2-methyl-butyrronitrile) (AMBN), 1,1-azobis(cyclohexane-1-carbonitrile), 2,2′-azobis(2,4-dimethyl-valeronitrile), or mixtures thereof, peroxides or hydroperoxides such as benzoyl peroxide, tert-butyl perbenzoate, tert-butyl peroxide, tert-butyl hydroperoxide, tert-butyl peroctoate, or mixtures thereof, or mixtures thereof; and/or in said process the radical polymerization initiator (vi) is used in a molar amount, obtainable from the ratio between the mass of the monomers used in said process and the weight average molecular weight to be obtained (M.sub.w target) for the single polymeric arms of the lipophilic copolymer comprising polar multi-blocks having general formula (I), said ratio being obtained from the Formula (A) reported below: $\begin{array}{cc}{\mathrm{moles}}_{\mathrm{Initiator}}+{\mathrm{moles}}_{\mathrm{RAFT}}=\frac{{\mathrm{grams}}_{\mathrm{monomers}}}{{\mathrm{Mw}}_{\mathrm{target}}}& \mathrm{Formula}\left(A\right)\end{array}$ wherein: grams.sub.monomers is the mass in grams of the monomers (i) and (ii); moles.sub.RAFT is the number of moles of the chain transfer agent of the RAFT thiocarbonyl thio type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v); moles.sub.Initiator is the number of moles of initiator of radical polymerization initiator (vi); and/or in said process the chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v) is selected from the group consisting of: dithioesters; trithiocarbonates; xanthates; dithiocarbamates, or mixtures thereof, and/or in said process the chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v) is used in a molar amount, obtainable from the ratio between the mass of the monomers used in said process and the weight average molecular weight to be obtained (M.sub.w target) for the single polymeric arms of the lipophilic copolymer comprising polar multi-blocks having general formula (I), said ratio being obtained from the Formula (A) reported above; and/or in said process the chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v) and the radical polymerization initiator (vi) are used in a molar ratio comprised between 1 and 5.

9. The process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 7, wherein said process is carried out in two stages as reported in the following Scheme 1: ##STR00023## wherein I represents the radical polymerization initiator (vi), RAFT represents the chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v), y, B, t, A, j, C and m, have the same meanings reported above in the definition of the general formula (I), k in said general formula (I) is 0, y′=t*y*s wherein s=1.

10. The process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 9, wherein said process according to Scheme 1 comprises the following two stages: (a.sub.1) dissolving in at least one apolar organic solvent, at least one lipophilic monomer having general formula (II) (i), at least one radical polymerization initiator (vi) and at least one chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v), said stage (a.sub.1) being carried out at a temperature comprised between 50° C. and 150° C., for a time comprised between 1 hour and 8 hours; (a.sub.2) adding to the solution obtained in the aforesaid stage (a.sub.1), at least one polar monomer (ii), optionally, at least one polar polyfunctional monomer (iv), and at least one radical polymerization initiator (vi), previously emulsified in the same organic apolar solvent used in stage (a.sub.1), using at least one surfactant (iii), said stage (a.sub.2) being carried out at a temperature comprised between 50° C. and 150° C., for a time comprised between 1 hour and 6 hours.

11. The process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 7, wherein said process is carried out in two stages as reported in the following Scheme 2: ##STR00024## wherein I represents the radical polymerization initiator (vi), RAFT represents the chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v), y, B, k, A, j, s, t and C, have the same meanings reported above in the definition of the general formula (I), y′=t*y*s and k′=k*t*s.

12. The process for the preparation of a lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 11, wherein said process according to Scheme 2 comprises the following two stages: (b.sub.1) dissolving in at least one apolar solvent, at least one lipophilic monomer having general formula (II) (i), at least one radical polymerization initiator (vi), at least one chain transfer agent of the thiocarbonyl thio RAFT type (“Reversible Addition Fragmentation Chain Transfer Polymerization”) (v), an amount comprised between 30% by weight and 95% by weight, of at least one polar monomer (ii) with respect to the total weight of said polar monomer (ii), and an amount comprised between 30% by weight and 95% by weight, of at least one surfactant (iii), with respect to the total weight of said surfactant (iii), said stage (b.sub.1) being carried out at a temperature comprised between 50° C. and 150° C., for a time comprised between 1 hour and 8 hours; (b.sub.2) adding to the solution obtained in the aforesaid stage (b.sub.1), the remaining part of said at least one polar monomer (ii), optionally, at least one polar polyfunctional monomer (iv), and at least one radical polymerization initiator (vi), previously emulsified in the same organic apolar solvent used in stage (b.sub.1), using the remaining part of said at least one surfactant, said stage (b.sub.2) being carried out at a temperature comprised between 50° C. and 150° C., for a time comprised between 1 hour and 8 hours.

13. A lubricating composition containing at least one lubricating base oil selected from the group consisting of lubricating base oils of mineral origin, of synthetic origin, of vegetable origin, of animal origin, or mixtures thereof, and at least one lipophilic copolymer comprising polar multi-blocks having general formula (I) according to claim 1, said lipophilic copolymer comprising polar multi-blocks having general formula (I) being present in said lubricating composition in an amount comprised between 0.2% by weight and 40% by weight, with respect to the total weight of said lubricating composition.

Description

EXAMPLES

[0170] The analysis and characterization methods reported below were used.

Molecular Characterization

[0171] The monomer conversions were determined by .sup.1H-NMR (NMR Bruker 500 Ultrashield Plus spectrometer) by taking a sample before the start of polymerization for each sample and calculating them from the variation of the ratio between the proton signals [—OCH.sub.2—] and [—OCH.sub.3—] (comprised between 3.6 ppm and 4.5 ppm) and the proton signals [CH.sub.2═CX— wherein X═H or CH.sub.3](comprised between 5.5 ppm and 6.6 ppm) for the reaction mixture and for the finished sample.

[0172] The molecular weights were determined by gel permeation chromatography (GPC) [HPLC Hewlett Packard Series 1100 equipped with Waters Styragel HR3 and HR4 chromatography columns, refractive index detector (RID), solvent used tetrahydrofuran (THF) with a flow of 0.3 ml/min] using a calibration line obtained from polystyrene standards. Through said gel permeation chromatography (GPC) the average number of polymeric arms of the star structure lipophilic copolymer were also determined [through the ratio between the peak molecular weight of the star structure lipophilic copolymer (M.sub.p star) and the peak molecular weight of the polymeric arm (M.sub.p arm)] and the star conversion of the polymeric arm [through the ratio between the area of the integral of the peak molecular weight relative only to the star structure (I.sub.star) and the area of the integral of the total distribution of the molecular weights of the star structure lipophilic copolymer to be analysed (I.sub.arm+I.sub.star)], as illustrated in FIG. 1.

[0173] The weight average molecular weight to be obtained (M.sub.w target) of the polymeric arm of the lipophilic copolymer comprising polar multi-blocks having general formula (I), was determined in accordance with the above reported formula (A).

Example 1-13 (Comparative)

Synthesis of Lipophilic Copolymers Comprising Polar Multi-Blocks by One-Stage Process

[0174] The preparation of Example 5 is reported in detail.

[0175] Methyl methacrylate (MMA) (Aldrich), long chain monomers [dodecyl methacrylate (LMA) and octadecyl methacrylate (SMA)] (Aldrich), the lubricating base oil (ETRO 4) (Petronas), the surfactant Triton® X-100 (polyethylene glycol tert-octyl phenyl ether) (Dow Chemical Company), 2-hydroxyethyl methacrylate (HEMA) (Aldrich) and pentaerythritol tetraacrylate (PETA) (Aldrich) were separately degassed by nitrogen flow for 45 minutes.

[0176] Subsequently, it was put in a 250 ml 3-necked flask, equipped with a mechanical stirrer, nitrogen inlet and cooling condenser, as follows (hereinafter MW=molecular weight): 98 g of ETRO 4, 28.6 g of LMA (MW=264.2 g/mol; 0.108 moles), 3.57 g of SMA (MW=316.0 g/mol; 2.25×10.sup.−2 moles), 6.3 g of MMA (MW=100.1 g/mol; 6.29×10.sup.−2 moles), 207 mg of 2-cyano-2-propyl dithiobenzoate (Aldrich) (RAFT) (MW=221.34 g/mol; 9.35×10.sup.−4 moles), 2 g of Triton® X-100 (average MW=625 g/mol; 3.20×10.sup.−3 moles), 4 g of HEMA (MW=130.14 g/mol; 3.07×10.sup.−2 moles) and 370 mg of PETA (MW=352.34 g/mol; 1.05×10.sup.−3 moles): the obtained mixture was left, under stirring, in a nitrogen atmosphere, for 15 minutes. Subsequently, the flask was placed in an oil bath thermostated at a temperature of 95° C. and 90 mg of 2,2′-azobis(2-methyl-butyronitrile) (VAZO™ 67) (DuPont) (MW=192.26 g/mol; 2.34×10.sup.−4 moles) were added to the reaction mixture, in order to initiate the polymerization reaction. After 2 hours, a further 45 mg of VAZO™ 67 (MW=192.26 g/mol; 1.17×10.sup.−4 moles) were added to the reaction mixture, in a nitrogen atmosphere, in order to carry out the finishing of the reaction of polymerization. After a further 1.5 hours, the flask was removed from the oil bath, exposed to the air for the atmospheric oxygen to terminate the polymerization reaction, poured into a suitable container and subjected to characterization by gel permeation chromatography (GPC) and .sup.1H-NMR: the results obtained are reported in Table 1.

[0177] FIG. 2 shows the layout of the gel permeation chromatography (GPC) of the lipophilic copolymer comprising polar multi-blocks obtained in said Example 5.

[0178] Examples 1-4 and 6-11 were carried out as described above for Example 5 using the same amounts of lipophilic monomers MMA, LMA and SMA, the same amount of polar monomer HEMA, the same amount of ETRO 4 lubricating base oil, the same amount of Triton X-100 surfactant, while the amounts of VAZO™ 67 and of RAFT were calculated on the basis of the desired weight average molecular weight (M.sub.w target), using the Formula A reported above: with the same weight average molecular weight desired (M.sub.w target), the parameter that has been changed is the amount of the PETA monomer.

[0179] Examples 12 and 13 were instead carried out without using RAFT.

[0180] In all the examples, the final product obtained was a solution of the lipophilic copolymer containing polar multi-blocks in ETRO 4 lubricating base oil and the amount of said copolymer present in said solution was equal to 32% by weight with respect to the total weight of said solution.

TABLE-US-00001 TABLE 1 Conversions by .sup.−1H-NMR MMA.sup.(1)- M.sub.w PETA.sup.(2) LMA.sup.(1)- target.sup.(3) final M.sub.w.sup.(4) final (% by SMA.sup.(1) HEMA.sup.(2) PETA.sup.(2) Example (g/mol) (g/mol) PDI.sup.(5) weight) (%) (%) (%) 1 50000 209800 2.1 0.25 88.3 >99 >99 2 50000 335000 2.5 0.30 89.0 >99 >99 3 50000 440500 2.6 0.40 75.2 >99 >99 4 50000 439500 2.5 0.50 66.8 82.4 >99 5 30000 137400 1.5 0.25 93.4 >99 >99 6 30000 230900 1.9 0.30 94.1 98.6 >99 7 30000 332000 2.7 0.40 92.7 >99 >99 8 30000 389600 2.5 0.50 87.1 98.2 >99 9 15000 71100 1.5 0.25 98.4 >99 >99 10 15000 169600 2.3 0.50 96.8 >99 >99 11 15000 247800 2.5 1.01 54.7 90.7 >99 12 30000 n.d..sup.(6) n.d..sup.(6) 0.50 n.d..sup.(6) n.d..sup.(6) n.d..sup.(6) 13 15000 n.d..sup.(6) n.d..sup.(6) 0.50 n.d..sup.(6) n.d..sup.(6) n.d..sup.(6) .sup.(1)lipophilic monomers; .sup.(2)polar monomers; .sup.(3)weight average molecular weight of the lipophilic copolymer comprising polar multi-blocks to be obtained; .sup.(4)weight average molecular weight of the lipophilic copolymer comprising polar multi-blocks obtained; .sup.(5)polydispersity index (PDI), corresponding to the ratio (M.sub.w/M.sub.n) between the weight average molecular weight (M.sub.w) and the number average molecular weight (M.sub.n) of the obtained lipophilic copolymer comprising polar multi-blocks; .sup.(6)not determined.

Examples 14-22

[0181] Synthesis of Star Structure Lipophilic Copolymers Comprising Polar Multi-Blocks by Two-Stage Process [Stage (a.sub.1) and Stage (a.sub.2)] Illustrated in Scheme 1

[0182] The preparation of Example 14 is reported in detail.

Stage (a.SUB.1.)

[0183] Methyl methacrylate (MMA) (Aldrich), long chain monomers [dodecyl methacrylate (LMA) and octadecyl methacrylate (SMA)] (Aldrich), the lubricating base oil (ETRO 4) (Petronas), the surfactant Triton® X-100 (polyethylene glycol tert-octyl phenyl ether) (Dow Chemical Company), 2-hydroxyethyl methacrylate (HEMA) (Aldrich) and pentaerythritol tetraacrylate (PETA) (Aldrich) were separately degassed by nitrogen flow for 45 minutes.

[0184] Subsequently, it was put in a 250 ml 3-necked flask, equipped with a mechanical stirrer, nitrogen inlet and cooling condenser, as follows: 83 g of ETRO 4 lubricating base oil, 28.6 g of LMA (MW=264.2 g/mol; 0.108 moles), 3.57 g of SMA (MW=316.0 g/mol; 2.25×10.sup.−2 moles), 6.3 g of MMA (MW=100.1 g/mol; 6.29×10.sup.−2 moles), 207 mg of 2-cyano-2-propyl dithiobenzoate (Aldrich) (RAFT) (MW=221.34 g/mol; 9.35×10.sup.−4 moles): the obtained mixture was left, under stirring, in a nitrogen atmosphere, for 15 minutes. Subsequently, the flask was placed in an oil bath thermostated at a temperature of 95° C. and 90 mg of 2,2′-azobis(2-methyl-butyronitrile) (VAZO™ 67) (DuPont) (MW=192.26 g/mol; 2.34×10.sup.−4 moles) were added to the reaction mixture, in order to initiate the polymerization reaction.

Stage (a.SUB.2.)

[0185] After 1 hour and 45 minutes, an emulsion containing 15 g of ETRO 4, 2 g of Triton® X-100 (average MW=625 g/mol; 3.2×10.sup.−3 moles), 4 g of HEMA (MW=130.14 g/mol; 3.07×10.sup.−2 moles) and 370 mg of PETA (MW=352.34 g/mol; 1.05×10.sup.−3 moles) and 23 mg of VAZO™ 67 (MW=192.26 g/mol; 1.2×10.sup.−4 moles), previously degassed and mixed for 45 minutes, were added to the reaction mixture obtained in Stage (a.sub.1) in a nitrogen atmosphere. After a further 4 hours, the flask was removed from the oil bath, exposed to the air for the atmospheric oxygen to terminate the polymerization reaction, poured into a suitable container and subjected to a gel permeation chromatography (GPC) and .sup.1H-NMR: the results obtained are reported in Table 2.

[0186] FIG. 3 shows the layout of the gel permeation chromatography (GPC) of the lipophilic copolymer comprising polar multi-blocks obtained in said Example 15: the continuous layout is related to the star structure copolymer comprising polar multi-blocks (Mp star) obtained in stage (a.sub.2); the dashed trace is related to the copolymer comprising polar multi-blocks (Mp arm) obtained in stage (a.sub.1).

[0187] Examples 15-19 were carried out as described above for Example 14 using the same amounts of lipophilic monomers MMA, LMA and SMA, the same amount of polar monomer HEMA, the same amount of ETRO 4 lubricating base oil, the same amount of Triton X-100 surfactant, while the amounts of VAZO™ 67 and of RAFT were calculated on the basis of the desired weight average molecular weight (target M.sub.w target), using the Formula A reported above: with the same average molecular weight desired weight (target M.sub.w), the parameter that has been changed is the amount of the PETA monomer.

[0188] Examples 20, 21 and 22, on the other hand, were carried out using 646 mg of 2-cyano-2-propyl dodecyl trithiocarbonate (Aldrich) (RAFT) (MW=345.63 g/mol; 1.87×10.sup.−3 moles), instead of 2-cyano-2-propyl dithiobenzoate (RAFT).

[0189] In all the examples, the final product obtained was a solution of the lipophilic copolymer containing polar multi-blocks with a mainly star structure in ETRO 4 lubricating base oil and the amount of said copolymer present in said solution was equal to 32% by weight with respect to the total weight of said solution.

TABLE-US-00002 TABLE 2 Conversions by .sup.−1H-NMR GPC analysis MMA.sup.(4)- M.sub.w PETA.sup.(5) M.sub.p M.sub.w M.sub.w Average Star LMA.sup.(4)- EXAM- target.sup.(3) (% by arm.sup.(6) arm.sup.(11) PDI M.sub.p star.sup.(12) PDI number con- SMA.sup.(4) HEMA.sup.(5) PETA.sup.(5) PLE RAFT (g/mol) weight) (g/mol) (g/mol) arm.sup.(7) star.sup.(8) (g/mol) star.sup.(9) of arms version.sup.(10) (%) (%) (%) 14 DB.sup.(1) 30000 0.25 27900 27500 1.14 232800 204200 1.22 8.4 68.6 93.8 98.3 >99 15 DB.sup.(1) 30000 0.50 32000 31500 1.16 268600 278700 1.15 8.4 76.4 93.1 98.9 >99 16 DB.sup.(1) 30000 0.75 31500 30500 1.2 293900 318800 1.2 9.3 79.7 94.2 >99 >99 17 DB.sup.(1) 15000 0.25 19100 18900 1.13 205200 226700 1.35 10.7 74.9 97.8 >99 >99 18 DB.sup.(1) 15000 0.50 19500 19200 1.13 199400 199800 1.08 10.2 73.8 96.7 >99 >99 19 DB.sup.(1) 15000 1.01 18200 18000 1.12 178600 183000 1.08 9.8 79.5 96.7 >99 >99 20 TTC.sup.(2) 15000 0.25 22400 22000 1.23 280900 337800 1.46 12.5 31.4 99.0 98.8 >99 21 TTC.sup.(2) 15000 0.50 21300 21100 1.22 242500 326100 1.24 11.4 36.5 96.6 >99 >99 22 TTC.sup.(2) 15000 1.01 22200 21700 1.21 219900 242700 1.37 9.9 60.8 97.1 >99 >99 .sup.(1)2-cyano-2-propyl dithiobenzoate; .sup.(2)2-cyano-2-propyl dodecyl trithiocarbonate; .sup.(3)weight average molecular weight to be obtained for the polymeric arm of the star structure lipophilic copolymer comprising polar multi-blocks; .sup.(4)lipophilic monomers; .sup.(5)polar monomers; .sup.(6)peak molecular weight of the polymeric arm of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(7)polydispersity index (PDI) corresponding to the ratio (M.sub.w/M.sub.n) between the weight average molecular weight (M.sub.w) and the number average molecular weight (M.sub.n) of the polymeric arm of the obtained star structure lipophilic copolymer comprising polar multi-blocks; .sup.(8)peak molecular weight of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(9)polydispersity index (PDI) corresponding to the ratio (M.sub.w/M.sub.n) between the weight average molecular weight (M.sub.w) and the number average molecular weight (M.sub.n) of the lipophilic copolymer comprising polar multi-blocks obtained; .sup.(10)star conversion of the polymeric arm; .sup.(11)weight average molecular weight of the polymeric arm of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(12)weight average molecular weight of the star structure lipophilic copolymer obtained comprising polar multi-blocks.

Examples 23-35

[0190] Synthesis of Star Structure Lipophilic Copolymers Comprising Polar Multi-Blocks by Two-Stage Process [Stage (b.sub.1) and Stage (b.sub.2)]

[0191] The preparation of Example 24 is reported in detail.

Stage (b.SUB.1.)

[0192] Methyl methacrylate (MMA) (Aldrich), long chain monomers [dodecyl methacrylate (LMA) and octadecyl methacrylate (SMA)] (Aldrich), the lubricating base oil (ETRO 4) (Petronas), the surfactant Triton® X-100 (polyethylene glycol tert-octyl phenyl ether) (Dow Chemical Company), 2-hydroxyethyl methacrylate (HEMA) (Aldrich) and pentaerythritol tetraacrylate (PETA) (Aldrich) were separately degassed by nitrogen flow for 45 minutes.

[0193] Subsequently, it was put in a 250 ml 3-necked flask, equipped with a mechanical stirrer, nitrogen inlet and cooling condenser, as follows: 88 g of ETRO 4 lubricating base oil, 28.6 g of LMA (MW=264.2 g/mol; 0.108 moles), 3.57 g of SMA (MW=316.0 g/mol; 2.25×10.sup.−2 moles), 6.3 g of MMA (MW=100.1 g/mol; 6.29×10.sup.−2 moles), 207 mg of 2-cyano-2-propyl dithiobenzoate (Aldrich) (RAFT) (MW=221.34 g/mol; 9.35×10.sup.−4 moles), 1.5 g of Triton® X-100 (average MW=625 g/mol; 2.40×10.sup.−3 moles) and 3 g of HEMA (MW=130.14 g/mol; 2.31×10.sup.−2 moles): the mixture obtained was left, under stirring, in a nitrogen atmosphere, for 15 minutes. Subsequently, the flask was placed in an oil bath thermostated at a temperature of 95° C. and 90 mg of 2,2′-azobis (2-methyl-butyronitrile) (VAZO™ 67) (DuPont) (MW=192.26 g/mol; 4.68×10.sup.−4 moles) was added to the reaction mixture, in order to initiate the polymerization reaction.

Stage (b.SUB.2.)

[0194] After 1 hour and 45 minutes, an emulsion containing 10 g of ETRO 4, 0.5 g of Triton® X-100 (average MW=625 g/mol; 8.00×10.sup.−4 moles), 1 g of HEMA (MW=130.14 g/mol; 7.68×10.sup.−3 moles) and 370 mg of PETA (MW=352.34 g/mol; 1.05×10.sup.−3 moles) and 23 mg of VAZO™ 67 (MW=192.26 g/mol; 1.2×10.sup.−4 moles), previously degassed and mixed for 45 minutes, were added to the reaction mixture obtained in Stage (b.sub.1) in a nitrogen atmosphere. After a further 4 hours, the flask was removed from the oil bath, exposed to the air for the atmospheric oxygen to terminate the polymerization reaction, poured into a suitable container and subjected to a gel permeation chromatography (GPC) and .sup.1H-NMR: the results obtained are reported in Table 3.

[0195] FIG. 4 shows the gel permeation chromatography (GPC) of the lipophilic copolymer comprising polar multi-blocks obtained in said Example 24: the continuous trace is related to the star structure copolymer comprising polar multi-blocks (M.sub.p star) obtained in stage (b.sub.2); the dashed trace is related to the copolymer comprising polar multi-blocks (M.sub.p arm) obtained in stage (b.sub.1).

[0196] Examples 23 and 25-28 were carried out as described above for Example 24 using the same amounts of lipophilic monomers MMA, LMA and SMA, the same amount of polar monomer HEMA, the same amount of ETRO 4 lubricating base oil, the same amount of Triton X-100 surfactant, while the amounts of VAZO™ 67 and of RAFT were calculated on the basis of the desired weight average molecular weight (M.sub.w target), using the Formula A reported above: with the same desired weight average molecular weight (M.sub.w target), the parameter that has been changed is the amount of the PETA monomer.

[0197] Examples 29 and 30, on the other hand, were carried out using 646 mg of 2-cyano-2-propyl dodecyl trithiocarbonate (Aldrich) (RAFT) (MW=345.63 g/mol; 1.87×10.sup.−3 moles), instead of 2-cyano-2-propyl dithiobenzoate (RAFT).

[0198] Example 31 was instead carried out using 4.25 mg of Eni MX 3280 surfactant (calcium dialkylbenzene sulfonate) (Eni), 45% by weight in Eni SN 150 lubricating base oil (average MW=968.1 g/mol; 1.97×10.sup.−3 moles) instead of Triton® X-100.

[0199] Example 32 was instead carried out using 324 mg of N,N′-bis-methylene bis-acrylamide (BAAm) (Aldrich) (MW=154.17 g/mol; 2.1×10.sup.−3 moles) instead of PETA.

[0200] Example 35 was instead carried out using 1.69 mg of 2,2′-bis [4-(methacryloxy-polyethoxy)-phenyl]-propane [u+v=10 in the general formula (IX)] (Aldrich) (MW=804 g/mol; 2.1×10.sup.−3 moles) instead of PETA.

[0201] Examples 33 and 34, on the other hand, were carried out using a different amount of HEMA (see Table 3).

[0202] In all the examples, the final product obtained was a solution of the star structure lipophilic copolymer containing polar multi-blocks in ETRO 4 lubricating base oil and the amount of said copolymer present in said solution was equal to 32% by weight with respect to the total weight of said solution.

TABLE-US-00003 TABLE 3 Poly- functional Conversions by .sup.−1H-NMR polar GPC analysis MMA.sup.(4)- HEMA M.sub.w monomer M.sub.p M.sub.w M.sub.w Average Star LMA.sup.(4)- EXAM- (% by target.sup.(3) (% by arm.sup.(6) arm.sup.(11) PDI M.sub.p star.sup.(12) PDI number con- SMA.sup.(4) HEMA.sup.(5) PETA.sup.(5) PLE weight) (g/mol) weight) (g/mol) (g/mol) arm.sup.(7) star.sup.(8) (g/mol) star.sup.(9) of arms version.sup.(10) (%) (%) (%) 23 8.7 30000 0.25 31500 31800 1.18 107600 86800 1.32 3.4 78.4 94.1 98.5 >99 24 8.7 30000 0.50 34700 35100 1.21 152300 161800 1.18 4.4 74.4 95.6 98.9 >99 25 8.7 30000 0.75 35700 35800 1.19 180000 167900 1.21 5.0 79.4 96.1 >99 >99 26 8.7 15000 0.25 19800 15500 1.15 90300 77000 1.18 4.6 71.1 97.9 98.9 >99 27 8.7 15000 0.50 22800 22300 1.18 118700 108900 1.22 5.2 76.5 97.3 >99 >99 28 8.7 15000 1.01 21200 20900 1.17 119700 114000 1.23 5.6 80.9 97.8 >99 >99 29 8.7 15000 0.25 23800 24000 1.25 54200 79700 1.22 2.3 65.6 97.8 98.5 >99 30 8.7 15000 0.50 24200 24400 1.25 98800 94700 1.25 4.1 72.2 98.1 >99 >99 31 8.7 15000 1.01 21600 32000 1.45 197100 256000 1.85 9.1 85.4 97.7 >99 >99 32 8.7 15000 0.25 21200 21000 1.15 47600 66700 1.15 2.2 58.3 97.5 >99 >99 33 4.3 15000 0.50 20900 20500 1.15 113700 100000 1.21 5.4 97.3 97.3 97.8 >99 34 17.4 15000 0.75 22000 23000 1.18 99400 90700 1.23 4.5 97.6 97.6 >99 >99 35 8.7 15000 0.25 21200 20600 1.15 175100 160400 1.09 8.3 97.5 97.5 >99 >99 .sup.(3)weight average molecular weight to be obtained for the polymeric arm of the star structure lipophilic copolymer comprising polar multi-blocks; .sup.(4)lipophilic monomers; .sup.(5)polar monomers; .sup.(6)peak molecular weight of the polymeric arm of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(7)polydispersity index (PDI) corresponding to the ratio (M.sub.w/M.sub.n) between the weight average molecular weight (M.sub.w) and the number average molecular weight (M.sub.n) of the polymeric arm of the obtained star structure lipophilic copolymer comprising polar multi-blocks; .sup.(8)peak molecular weight of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(9)polydispersity index (PDI) corresponding to the ratio (M.sub.w/M.sub.n) between the weight average molecular weight (M.sub.w) and the number average molecular weight (M.sub.n) of the lipophilic copolymer comprising polar multi-blocks obtained; .sup.(10)star conversion of the polymeric arm; .sup.(11)weight average molecular weight of the polymeric arm of the star structure lipophilic copolymer obtained comprising polar multi-blocks; .sup.(12)weight average molecular weight of the star structure lipophilic copolymer obtained comprising polar multi-blocks.

Example 36-59

Lubricating Compositions Containing Lipophilic Copolymers Containing Polar Multi-Groups

[0203] The lubricating compositions for applications such as hydraulic oils have been prepared by mixing the lipophilic copolymers containing polar multi-groups obtained in the examples reported above with a mixture of mineral lubricating base oils belonging to Group I (API classification): said lubricating compositions also contain a package of additives.

[0204] Lipophilic copolymers containing polar multi-groups were added as a solution in ETRO 4 base oil at a concentration of 32% by weight, as they were obtained in the examples above reported (the numbers of the examples are reported in Tables 4-6 below). The solutions of the various lipophilic copolymers containing polar multi-groups have been added in such an amount as to obtain lubricating compositions with a kinematic viscosity value (“Kinematic Viscosity”—KV), at 40° C., of about 46 mm.sup.2/s.

[0205] The kinematic viscosity (KV), at 40° C. and 100° C., was determined by the ASTM D445-18 method.

[0206] The viscosity index (VI) was determined by the ASTM D2270-10 (2016) method.

[0207] The Pour Point was determined by the ASTM D97-17b method.

[0208] The lubricating compositions were also subjected to the KRL test (CEC L-45-A-99) for the evaluation of the mechanical shear stability of the lipophilic copolymers containing polar multi-groups contained therein, using an apparatus equipped with a rotating bearing immersed in the lubricating composition to be analysed. The test was carried out for 20 hours with a load of 5000 N, at a temperature of 40° C. and at 1450 rpm. The kinematic viscosity data at 100° C. of the oil, before the KRL test and after the test, were determined by the ASTM D445-18 method. The KRL test delivers as a result the percentage of loss of the kinematic viscosity measured at 100° C.

[0209] The data obtained from the analyses carried out are reported in Tables 4, 5 and 6. In particular: [0210] Table 4 shows the data obtained from the carried out analyses of the lubricating compositions containing the lipophilic copolymers containing polar multi-groups obtained through the one-stage process (comparative); [0211] Table 5 shows the data obtained from the carried out analyses of the lubricating compositions containing the star structure lipophilic copolymers containing polar multi groups obtained through the two-stage process [stage (a.sub.1) and stage (a.sub.2)]; [0212] Table 6 shows the data obtained from the carried out analyses of the lubricating compositions containing the star structure lipophilic copolymers containing polar multi groups obtained through the two-stage process [stage (b.sub.1) and stage (b.sub.2)].

[0213] From the data reported in Tables 4, 5 and 6, it can be deduced that the lubricating compositions containing the lipophilic copolymers containing polar multi-groups obtained in Examples 1-13 (comparative) show a greater loss of viscosity with respect to the lubricating compositions containing the star structure lipophilic copolymers containing polar multi-groups obtained in Examples 15-22 and 23-35 according to the present disclosure. Said behaviour is particularly clear when comparing the results of Example 41 (comparative) with those of Examples 48 (disclosure), 49 (disclosure), 50 (disclosure), 54 (disclosure), 55 (disclosure), and 56 (disclosure): in the latter examples, with a lower copolymer content than in Example 41 (comparative), a better thickening capacity and a lower viscosity loss at the KRL test and therefore a better mechanical shear stability are obtained.

TABLE-US-00004 TABLE 4 KINEMATIC VISCOSITY VISCOSITY COPOLYMER ANALYSIS LOSS SOLUTION COPOLYMER (KV) POUR AFTER COPOLYMER CONTENT CONTENT 40° C. 100° C. VISCOSITY POINT KRL TEST EXAMPLE EXAMPLE (% m/m) (% m/m) (mm.sup.2/s) (mm.sup.2/s) INDEX (VI) (° C.) (%) 36 1 4.3 1.38 44.35 8.19 161 −36 27.7 (comparative) 37 5 11.7 3.74 46.82 8.54 161 −36 21.3 (comparative) 38 6 6 1.92 44.46 8.02 154 −36 23.1 (comparative) 39 7 4 1.28 47.43 9.11 177 −36 36.5 (comparative) 40 8 3.8 1.22 45.26 8.49 167 −36 31.8 (comparative) 41 9 18 5.76 46.47 8.3 155 −39 12.1 (comparative) 42 10 8 2.56 50.25 9.41 174 −39 31.5 (comparative) 43 12 5 1.6 LITTLE SOLUBLE IN OIL, — — (comparative) CROSS-LINKED COPOLYMER 44 13 5 1.6 LITTLE SOLUBLE IN OIL, — — (comparative) CROSS-LINKED COPOLYMER

TABLE-US-00005 TABLE 5 KINEMATIC VISCOSITY VISCOSITY COPOLYMER ANALYSIS LOSS SOLUTION COPOLYMER (KV) POUR AFTER COPOLYMER CONTENT CONTENT 40° C. 100° C. VISCOSITY POINT KRL TEST EXAMPLE EXAMPLE (% m/m) (% m/m) (mm.sup.2/s) (mm.sup.2/s) INDEX (VI) (° C.) (%) 45 14 13.18 4.21 45.76 8.22 155 −36 15.3 46 15 12 3.84 46.35 8.29 155 −36 18.7 47 16 10.5 3.36 44.71 8.03 154 −36 17.1 48 17 16.06 5.13 44.62 7.91 150 −39 8 49 18 14 4.48 43.78 7.63 144 −39 6.5 50 19 15.4 4.92 45.32 7.98 149 −39 8.1

TABLE-US-00006 TABLE 6 KINEMATIC VISCOSITY VISCOSITY COPOLYMER ANALYSIS LOSS SOLUTION COPOLYMER (KV) POUR AFTER COPOLYMER CONTENT CONTENT 40° C. 100° C. VISCOSITY POINT KRL TEST EXAMPLE EXAMPLE (% m/m) (% m/m) (mm.sup.2/s) (mm.sup.2/s) INDEX (VI) (° C.) (%) 51 23 15.39 4.92 44.99 8.21 159 −39 13.1 52 24 11.5 3.68 44.99 8.08 154 −39 15.8 53 25 11.5 3.68 45.95 8.23 155 −39 16.5 54 26 16 5.12 43.18 7.65 147 −39 7 55 27 14 4.48 43.50 7.7 147 −39 6.6 56 28 13.5 4.32 43.24 7.65 146 −39 8.4 57 33 18 5.76 45.24 8.01 153 −39 8.8 58 34 14.4 4.61 47.06 8.25 151 −39 19.1 59 31 8 2.56 45.06 8.09 154 −39 20.3