WO2014106589A1 - Preparation of low-viscosity polymers - Google Patents

Preparation of low-viscosity polymers Download PDF

Info

Publication number
WO2014106589A1
WO2014106589A1 PCT/EP2013/077336 EP2013077336W WO2014106589A1 WO 2014106589 A1 WO2014106589 A1 WO 2014106589A1 EP 2013077336 W EP2013077336 W EP 2013077336W WO 2014106589 A1 WO2014106589 A1 WO 2014106589A1
Authority
WO
WIPO (PCT)
Prior art keywords
meth
acrylic acid
acid esters
formula
weight
Prior art date
Application number
PCT/EP2013/077336
Other languages
French (fr)
Inventor
Sofia M SIRAK
Christopher Paul Radano
Original Assignee
Evonik Oil Additives Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Evonik Oil Additives Gmbh filed Critical Evonik Oil Additives Gmbh
Publication of WO2014106589A1 publication Critical patent/WO2014106589A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
    • C10M107/20—Lubricating compositions characterised by the base-material being a macromolecular compound containing oxygen
    • C10M107/22—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M107/28—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C08F220/1812—C12-(meth)acrylate, e.g. lauryl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C08F220/1818—C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/08—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type
    • C10M2209/084—Acrylate; Methacrylate
    • C10M2209/0845—Acrylate; Methacrylate used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/011—Cloud point
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/019—Shear stability
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/02—Viscosity; Viscosity index
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/04—Molecular weight; Molecular weight distribution

Definitions

  • the present invention relates to a method for the preparation of low-viscosity polymers suitable as base fluids for lubricants.
  • the method comprises polymerizing specific (meth)acrylic acid esters in the presence of a cobalt catalytic chain transfer agent.
  • Lubricants typically contain a base fluid and variable amounts of additives.
  • a good lubricant should posses a high boiling and low freezing point, a high viscosity index, good thermal stability, low susceptibility to corrosion, and a high resistance to oxidation. These properties are significantly determined by the additives used. Therefore, a base fluid that can support a broad variety of additives is needed to improve the overall performance of the lubricant.
  • lubricant base fluids are subdivided into different groups.
  • Groups I to III encompass different mineral oils distinguished by their degree of saturation, sulphur content, and viscosity index.
  • Group IV encompasses polyalphaolefins.
  • Group V encompasses all other base fluids including napthenics, polyalkylene glycol oils, and esters.
  • Base fluids for lubricants may especially be oils having a kinematic viscosity in the range of 3 to 100 mm 2 /s, preferably 13 to 65 mm 2 /s measured at 40°C according to ASTM D 445.
  • mineral oil commonly refers to oils derived from crude oil fractions. Mineral oils of groups I to III are therefore regarded as native oils. In contrast, base fluids of groups IV and V are regarded as synthetic base fluids. Synthetic base fluids are growing in interest and are preferred over mineral oils due to their greater oxidative and chemical stability, improved viscosity index and reduced pour point. Further, their properties may be systematically controlled during synthesis to optimize the structure-property profile of the base fluids. Due to their synthesis from relatively pure raw material, synthetic base fluids also contain fewer unwanted by-products with deleterious effects.
  • Ester oils are group V base fluids that may have superior solubility, additive compatibility and viscosimetrics compared to other group IV and V base fluids.
  • a particular example of ester oils are polymers of (meth)acrylic acid esters.
  • Polymers of (meth)acrylic acid esters can be prepared by radical polymerization, in particular by catalytic chain transfer polymerization.
  • Catalytic chain transfer (CCT) is a process which involves adding a catalytic chain transfer reagent to a radical polymerization reaction to achieve greater control over the length of the resulting polymers.
  • cobalt porphyrins can be used as catalytic chain transfer reagents in the polymerization of methyl- methacrylate to reduce the molecular weight of the resulting poly-methyl- methacrylate (N. S. Enikolopyan et al., Journal of Polymer Science: Polymer Chemistry Edition, 1981 , vol. 19, pp. 879-889).
  • US 2009/0012231 A1 discloses macromonomers synthesized by cobalt-catalyzed chain transfer free radical polymerizations of (meth)acrylic monomers. It further discloses the preparation of a pigment dispersion from the reaction of said macromonomers with monomeric or oligomeric amines.
  • US 2009/0012231 A1 does not relate to the synthesis of low-viscosity polymers from methacrylic acid esters.
  • US 4,680,352 discloses the use of different Co(ll) chelates as catalytic chain transfer agents for controlling the molecular weight of homopolymers and copolymers produced in free radical polymerization processes.
  • US 4,680,352 relates to the polymerization of methacrylic acid ester monomers and styrene monomers.
  • the present invention aims at providing an improved method for the preparation of low viscosity polymers from (meth)acrylic acid esters.
  • the polymers prepared have a kinematic viscosity of less than 100 mm 2 /s measured at 100°C according to ASTM D 445. Further, the method should require low amounts of free radical initiator. Additionally, the polymers should have superior viscosity indices and comparable volatilities and much lower sulphur content, when compared to state of the art base fluids.
  • (meth)acrylic refers to either acrylic or to methacrylic, or mixtures of acrylic and methacrylic.
  • (meth)acrylate refers to either acrylate or to methacrylate, or mixtures of acrylate and methacrylate.
  • the present invention relates to a method for preparing a polymer composition having a kinematic viscosity of less than 100 mm 2 /s measured at 100°C according to ASTM D 445 from (meth)acrylic acid esters. This method comprises the steps of
  • R 1 represents a hydrogen atom or a methyl group
  • R 2 represents a Ci to C30 alkyl group
  • said reaction mixture comprises
  • the (meth)acrylic acid esters according to formula (I) may also be referred to as "C n (meth)acrylic acid esters” or “C n (meth)acrylates”. These terms refer to compounds according to formula (I), wherein R 2 represents a C n alkyl group.
  • Non-limiting examples of compounds of formula (I) include methyl-(meth)acrylate, ethyl-(meth)acrylate, n-propyl-(meth)acrylate, / ' so-propyl-(meth)acrylate, n-butyl- (meth)acrylate, teff-butyl-(meth)acrylate, pentyl-(meth)acrylate, cyclopentyl- (meth)acrylate, hexyl-(meth)acrylate, 2-ethylhexyl-(meth)acrylate, heptyl- (meth)acrylate, 2-terf-butylheptyl-(meth)acrylate, octyl-(meth)acrylate, 3-isopropyl- heptyl-(meth)acrylate, nonyl-(meth)acrylate, decyl-(meth)acrylate, undecyl- (meth)acrylate,
  • the monomer reaction mixture comprises from 40% to 100% by weight of (meth)acrylic acid esters according to formula (I) having a C 7 to C30 alkyl group, based on the total weight of (meth)acrylic acid esters according to formula (I), in order to get oil-soluble polymer compositions suitable as lubricant formulations.
  • polymers of a kinematic viscosity of less than 100 mm 2 /s, preferably less than 90 mm 2 /s, more preferably less than 80 mm 2 /s measured at 100°C according to ASTM D 445 can be prepared. Additionally, the polymer composition prepared by the inventive method are sulphur free.
  • the term "degree of linearity” refers to the amount of (meth)acrylic acid esters according to formula (I) having a linear alkyl group as substituent R 2 , based on the total weight of (meth)acrylic acid esters according to formula (I).
  • the degree of linearity of the (meth)acrylic acid esters according to formula (I) is at least 30%, preferably at least 70%, most preferably 100%.
  • R 2 in formula (I) represents a linear alkyl group. This means that the degree of linearity is 100%.
  • the reaction mixture prepared in step a) may additionally comprise a solvent.
  • the solvent may be selected according to the polarity of the monomers used. Suitable solvents include, for example, aromatic hydrocarbons such as, for example, benzene, toluene, and xylenes; ethers such as, for example, tetrahydrofuran, diethyl ether, ethylene glycol and polyethylene glycol monoalkyl and dialkyl ethers; alkyl esters of acetic, propionic and butyric acids; mixed ester-ethers, such as, for example, monoalkyl ether-monoalkanoate esters of ethylene glycol; ketones such as, for example, acetone, butanone, pentanone and hexanone; alcohols such as, for example, methanol, ethanol, propanol and butanol. Oils such as, for example, hydrocracked oil, petroleum oil, polyalphaolefins, esters or polymers
  • the Co(ll) complex used in the inventive method acts as a catalytic chain transfer agent.
  • a cobalt based catalytic chain transfer agent By using a cobalt based catalytic chain transfer agent it has surprisingly been found that polymer compositions of extremely low viscosity can be produced.
  • the amount of Co(ll) added to the reaction mixture in the form of a Co(ll) complex is preferably 30 to 500 ppm by weight, based on the total weight of (meth)acrylic acid esters, more preferably 30 to 100 ppm by weight, most preferably 50 to 100 ppm by weight.
  • Suitable examples of Co(ll) complexes of the present invention include complexes comprising Co(ll) and at least one of the ligands according to formulae (II) to (VII)
  • each R 3 independently represents a phenyl group or a Ci to C12 alkyl group, or two R 3 on adjacent carbon atoms together represent a C 5 to Cs alkylene group; each R 4 independently represents a hydrogen atom or a Ci to C12 alkyl group; each R 5 independently represents a hydroxyl group or an amino group; each R 6 independently represents a hydrogen atom, a Ci to C12 alkyl group, a phenyl group, a hydroxyphenyl group, or a Ci to C 4 alkoxyphenyl group; and each n independently represents an integer 2 or 3.
  • the Co(ll) complex comprises Co(ll) and a ligand of formula (VII). More preferably, the Co(ll) complex is 5,10,15,20- tetraphenyl-porphine Co(ll).
  • the radical initiator used in the inventive method may be any free radical initiator suitable for use in radical polymerization reactions. Such radical initiators are well known in the art. Azo compounds are particularly preferred radical initiators.
  • the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight, based on the total weight of (meth)acrylic acid esters, preferably in the range of 0.1 to 3% by weight, based on the total weight of (meth)acrylic acid esters. It has surprisingly been found that by varying the amount of initiator, polymer compositions of different viscosity and different pour points may be produced. To achieve a particularly low viscosity, the total amount of initiator added to the reaction mixture is preferably 0.1 to 1 .5% by weight, based on the total weight of (meth)acrylic acid esters.
  • the radical initiator may be added to the reaction mixture in a stepwise fashion to ensure that the radical initiator does not get depleted too quickly during long polymerization times. For example, a first dose of the radical initiator is added to the reaction mixture to start the polymerization reaction, then the reaction is allowed to proceed for a certain amount of time, then an additional dose of initiator is added, and so on. The total amount added in all steps, however, should not exceed the preferred total amount of radical initiator mentioned above.
  • the time interval between the additions of the different doses of radical initiator may be in the range of 10 minutes to 5 hours, preferably 30 to 60 minutes.
  • radical initiators include azo-compounds such as azobisisobutylonitrile (AIBN), 2,2'-Azobis(2-methylbutyronitrile), 2-(2-cyanobutan- 2-yldiazenyl)-2-methylbutanenitrile, and 1 ,1 -azobiscyclohexanecarbonitrile; peroxy compounds such as methyl-ethyl-ketone peroxide, acetylacetone peroxide, dilauryl peroxide, terf-butyl per-2-ethylhexaneoate, ketone peroxide, terf-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, terf-butyl peroxybenzoate, terf-butyl peroxyisopropylcarbonate, 2,5-bis- (2-ethylhexanoylperoxy)-2,
  • the reaction mixture may be reacted in step d) at standard ambient pressure, reduced pressure or elevated pressure.
  • the reaction temperature may in the range of -20°C to 200°C, preferably 50°C to 160°C, more preferably 80°C to 160°C.
  • the addition of the radical initiator in step c) and the reaction in step d) takes place in an inert gas atmosphere to prevent degradation of the radical initiator.
  • an inert gas atmosphere to prevent degradation of the radical initiator.
  • nitrogen gas is used as inert gas.
  • the reaction may be allowed to proceed in step d) for up to 12 hours, preferably for 10 minutes to 12 hours, more preferably for 1 to 6 hours.
  • the method comprises the steps of:
  • Co(ll) as a catalytic chain transfer agent in the form of a complex comprising Co(ll) and a ligand according to formula (VII) at a concentration of 30 ppm to 100 ppm by weight of Co(ll), based on the total weight of (meth)acrylic acid esters;
  • the present invention also relates to the use of a (meth)acrylic acid ester accordin to formula (VIII)
  • R 7 is a hydrogen atom or a methyl group
  • R 8 is a C12 to C30 alkyl group for the preparation of a polymer composition having a kinematic viscosity of less than 100 mm 2 /s, preferably less than 90 mnn 2 /s, more preferably less than 80 mm 2 /s measured at 100°C according to ASTM D 445.
  • R is a linear alkyl group.
  • R 8 is a CM to C30 alkyl group, even more preferably a linear C16 to C20 alkyl group.
  • the polymer composition is a composition of polymers of (meth)acrylic acid esters.
  • the present invention relates to a method of reducing the kinematic viscosity of a polymer composition, said method comprising a method for the preparation of a polymer composition, said method for the preparation of a polymer composition comprising the steps of:
  • R 9 is a hydrogen atom or a methyl group, and R 10 is a C 7 to C30 alkyl group;
  • the method for the preparation of a polymer composition is the method to prepare a polymer composition as described above.
  • the Co(ll) complex that is used as catalyst is the Co(ll) complex as described above.
  • EHMA ethyl-hexyl methacrylate
  • Isodecyl-methacrylate IDMA
  • Cio methacrylate 0.8% by weight C12 methacrylate
  • CM methacrylate 0.5% by weight
  • the degree of linearity of IDMA is approximately 0%.
  • Methacrylate from LIAL ® 125 alcohol (LIMA) is a mixture consisting of 24.3% by weight C12 methacrylate, 29.4% by weight C13 methacrylate, 28.4% by weight Ci 4 methacrylate, and 17.9% by weight C15 methacrylate.
  • LIMA degree of linearity of LIMA is approximately 40%.
  • Lauryl methacrylate (LMA) is a mixture consisting of 72.2% by weight C12 methacrylate, and 27.8% by weight Ci 4 methacrylate.
  • the degree of linearity of LIAL is approximately 100%.
  • DPMA is a mixture consisting of 24.6% by weight C12 methacrylate, 29.1 % by weight C13 methacrylate, 24.3% by weight Ci 4 methacrylate, and 22.0% by weight Ci5 methacrylate.
  • the degree of linearity of DPMA is approximately 80%.
  • SMA Stearyl methacrylate
  • Comparative example 1 250 g of EHMA were charged into a 500 mL 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
  • initiator solution composed of 25% 2-(2- cyanobutan-2-yldi
  • the kinematic viscosities of the polymers were measured according to ASTM D 445.
  • the polymer molecular weights were measured by gel permeation chromatography (GPC) calibrated using PMMA standards.
  • the sonic shear stability (SSI) was determined according to ASTM D 5621 .
  • the pour point was determined according to ASTM D 6749.
  • the viscosity index was determined according to ASTM D 2270.
  • Examples 2-6 demonstrate that the use of a cobalt based catalytic chain transfer agent for the polymerization of methacrylate monomers results in low viscosity polymers (see table 1 ), when the methacrylate monomers of the reaction mixture comprise at least 0.5 wt% (meth) acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), having a C12 to C30 alkyl group as substituent R 2 .
  • the molecular weight of the polymers indicates a degree of polymerization of about 10 units.
  • examples 4, 5 and 6 clearly demonstrate that with an increasing degree of linearity, a lower viscosity is obtainable.
  • Example 1 shows that when using (meth) acrylic acid esters according to formula (I), having a C 7 alkyl group as substituent R 2 in the reaction mixture, then polymer compositions with a kinematic viscosity of 103 mm 2 /s at 100°C and a molecular weight Mw of 3.2 kg/mol can be obtained.
  • Table 1 Viscosimetric data of examples 1 to 6. The amounts given are relative to the total weight of methacrylate monomers.
  • Cio methacrylate [% by weight] 98.7 0
  • Ci2 methacrylate [% by weight] 0.8 72.2 24.3 24.6
  • Ci3 methacrylate [% by weight] 29.4 29.1
  • Ci 5 methacrylate [% by weight] 17.9 22.0
  • Ci6 methacrylate [% by weight] 29.3
  • Ci8 methacrylate [% by weight] 69.8

Abstract

The present invention relates to a method for the preparation of low-viscosity polymers suitable as base fluids for lubricants. The method comprises polymerizing specific (meth)acrylic acid esters in the presence of a cobalt catalytic chain transfer agent.

Description

Preparation of Low-Viscosity Polymers
The present invention relates to a method for the preparation of low-viscosity polymers suitable as base fluids for lubricants. The method comprises polymerizing specific (meth)acrylic acid esters in the presence of a cobalt catalytic chain transfer agent.
The present invention relates to the field of lubrication. Lubricants typically contain a base fluid and variable amounts of additives. A good lubricant should posses a high boiling and low freezing point, a high viscosity index, good thermal stability, low susceptibility to corrosion, and a high resistance to oxidation. These properties are significantly determined by the additives used. Therefore, a base fluid that can support a broad variety of additives is needed to improve the overall performance of the lubricant.
According to the American Petroleum Institute (API) lubricant base fluids are subdivided into different groups. Groups I to III encompass different mineral oils distinguished by their degree of saturation, sulphur content, and viscosity index. Group IV encompasses polyalphaolefins. Group V encompasses all other base fluids including napthenics, polyalkylene glycol oils, and esters. Base fluids for lubricants may especially be oils having a kinematic viscosity in the range of 3 to 100 mm2/s, preferably 13 to 65 mm2/s measured at 40°C according to ASTM D 445.
The term mineral oil commonly refers to oils derived from crude oil fractions. Mineral oils of groups I to III are therefore regarded as native oils. In contrast, base fluids of groups IV and V are regarded as synthetic base fluids. Synthetic base fluids are growing in interest and are preferred over mineral oils due to their greater oxidative and chemical stability, improved viscosity index and reduced pour point. Further, their properties may be systematically controlled during synthesis to optimize the structure-property profile of the base fluids. Due to their synthesis from relatively pure raw material, synthetic base fluids also contain fewer unwanted by-products with deleterious effects.
Ester oils are group V base fluids that may have superior solubility, additive compatibility and viscosimetrics compared to other group IV and V base fluids. A particular example of ester oils are polymers of (meth)acrylic acid esters. Polymers of (meth)acrylic acid esters can be prepared by radical polymerization, in particular by catalytic chain transfer polymerization. Catalytic chain transfer (CCT) is a process which involves adding a catalytic chain transfer reagent to a radical polymerization reaction to achieve greater control over the length of the resulting polymers. It is known that cobalt porphyrins can be used as catalytic chain transfer reagents in the polymerization of methyl- methacrylate to reduce the molecular weight of the resulting poly-methyl- methacrylate (N. S. Enikolopyan et al., Journal of Polymer Science: Polymer Chemistry Edition, 1981 , vol. 19, pp. 879-889).
US 2009/0012231 A1 discloses macromonomers synthesized by cobalt-catalyzed chain transfer free radical polymerizations of (meth)acrylic monomers. It further discloses the preparation of a pigment dispersion from the reaction of said macromonomers with monomeric or oligomeric amines. However, US 2009/0012231 A1 does not relate to the synthesis of low-viscosity polymers from methacrylic acid esters. US 4,680,352 discloses the use of different Co(ll) chelates as catalytic chain transfer agents for controlling the molecular weight of homopolymers and copolymers produced in free radical polymerization processes. In particular, US 4,680,352 relates to the polymerization of methacrylic acid ester monomers and styrene monomers.
The present invention aims at providing an improved method for the preparation of low viscosity polymers from (meth)acrylic acid esters. The polymers prepared have a kinematic viscosity of less than 100 mm2/s measured at 100°C according to ASTM D 445. Further, the method should require low amounts of free radical initiator. Additionally, the polymers should have superior viscosity indices and comparable volatilities and much lower sulphur content, when compared to state of the art base fluids.
In the context of the present invention, the term "(meth)acrylic" refers to either acrylic or to methacrylic, or mixtures of acrylic and methacrylic. Correspondingly, the term "(meth)acrylate" refers to either acrylate or to methacrylate, or mixtures of acrylate and methacrylate.
The present invention relates to a method for preparing a polymer composition having a kinematic viscosity of less than 100 mm2/s measured at 100°C according to ASTM D 445 from (meth)acrylic acid esters. This method comprises the steps of
a) preparing a reaction mixture comprising a (meth)acrylic acid ester according to formula (I) or a mixture of (meth)acrylic acid esters of formula (I)
Figure imgf000004_0001
wherein R1 represents a hydrogen atom or a methyl group, and R2 represents a Ci to C30 alkyl group;
b) adding a Co(ll) complex as a catalytic chain transfer agent to the reaction mixture;
c) adding a radical initiator; and
d) reacting the reaction mixture to obtain the polymer composition,
characterized in that
said reaction mixture comprises
i) from 0 to 60% by weight of the (meth)acrylic acid esters according to formula (I) based on the total weight of (meth) acrylic acid esters according to formula (I) have a Ci to C6 alkyl group as substituent R2, and ii) from 40 to 100% by weight of the (meth)acrylic acid esters according to formula (I) based on the total weight of (meth) acrylic acid esters according to formula (I) have a C7 to C30 alkyl group as substituent R2,
from which at least 0.5% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a C12 to C30 alkyl group as substituent R2, and wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight, based on the total weight of (meth)acrylic acid esters.
In the context of the present invention, the (meth)acrylic acid esters according to formula (I) may also be referred to as "Cn (meth)acrylic acid esters" or "Cn (meth)acrylates". These terms refer to compounds according to formula (I), wherein R2 represents a Cn alkyl group.
Non-limiting examples of compounds of formula (I) include methyl-(meth)acrylate, ethyl-(meth)acrylate, n-propyl-(meth)acrylate, /'so-propyl-(meth)acrylate, n-butyl- (meth)acrylate, teff-butyl-(meth)acrylate, pentyl-(meth)acrylate, cyclopentyl- (meth)acrylate, hexyl-(meth)acrylate, 2-ethylhexyl-(meth)acrylate, heptyl- (meth)acrylate, 2-terf-butylheptyl-(meth)acrylate, octyl-(meth)acrylate, 3-isopropyl- heptyl-(meth)acrylate, nonyl-(meth)acrylate, decyl-(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, oleyl- (meth)acrylate, cyclohexyl-(meth)acrylate, hexadecyl-(meth)acrylate, 2-methyl- hexadecyl-(meth)acrylate, heptadecyl-(meth)acrylate, 5-isopropylheptadecyl- (meth)acrylate, 4-fe/t-butyloctadecyl-(meth)acrylate, 5-ethyloctadecyl- (meth)acrylate, 3-isopropyloctadecyl-(meth)acrylate, octadecyl-(meth)acrylate, nonadecyl-(meth)acrylate, eicosyl-(meth)acrylate, cetyleicosyl-(meth)acrylate, stearyleicosyl-(meth)acrylate, docosyl-(meth)acrylate, eicosyltetratriacontyl- (meth)acrylate, and 2,3,4, 5-tetra-terf-butylcyclohexyl-(meth)acrylate. In the present invention, it is essential that the monomer reaction mixture comprises from 40% to 100% by weight of (meth)acrylic acid esters according to formula (I) having a C7 to C30 alkyl group, based on the total weight of (meth)acrylic acid esters according to formula (I), in order to get oil-soluble polymer compositions suitable as lubricant formulations.
In a preferred embodiment at least 20% by weight, more preferably at least 40% by weight, most preferably 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a C12 to C30 alkyl group as substituent R2.
In another preferred embodiment at least 0.5% by weight, more preferably at least 20% by weight, even more preferably at least 40% by weight, most preferably 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a CM to C30 alkyl group as substituent R2.
It has surprisingly been found that with the inventive method, polymers of a kinematic viscosity of less than 100 mm2/s, preferably less than 90 mm2/s, more preferably less than 80 mm2/s measured at 100°C according to ASTM D 445 can be prepared. Additionally, the polymer composition prepared by the inventive method are sulphur free.
It has also surprisingly been found that by varying the degree of linearity of the alkyl group R2, the viscosity of the polymers can be adjusted. In particular, a higher degree of linearity of the alkyl group R2 results in a lower viscosity.
In the context of the present invention, the term "degree of linearity" refers to the amount of (meth)acrylic acid esters according to formula (I) having a linear alkyl group as substituent R2, based on the total weight of (meth)acrylic acid esters according to formula (I). Preferably, the degree of linearity of the (meth)acrylic acid esters according to formula (I) is at least 30%, preferably at least 70%, most preferably 100%. That means that at least 30% by weight, preferably at least 70% by weight, most preferably 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters according to formula (I), have a linear alkyl group as substituent R2. In a particularly preferred example, R2 in formula (I) represents a linear alkyl group. This means that the degree of linearity is 100%.
It is particularly preferred that at least 20% by weight, more preferably at least 40% by weight, most preferably 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a linear C12 to C30 alkyl group as substituent R2. Even more preferably, 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a linear C16 to C20 alkyl group as substituent R2.
The reaction mixture prepared in step a) may additionally comprise a solvent. The solvent may be selected according to the polarity of the monomers used. Suitable solvents include, for example, aromatic hydrocarbons such as, for example, benzene, toluene, and xylenes; ethers such as, for example, tetrahydrofuran, diethyl ether, ethylene glycol and polyethylene glycol monoalkyl and dialkyl ethers; alkyl esters of acetic, propionic and butyric acids; mixed ester-ethers, such as, for example, monoalkyl ether-monoalkanoate esters of ethylene glycol; ketones such as, for example, acetone, butanone, pentanone and hexanone; alcohols such as, for example, methanol, ethanol, propanol and butanol. Oils such as, for example, hydrocracked oil, petroleum oil, polyalphaolefins, esters or polymers of the present invention may also be used.
The Co(ll) complex used in the inventive method acts as a catalytic chain transfer agent. By using a cobalt based catalytic chain transfer agent it has surprisingly been found that polymer compositions of extremely low viscosity can be produced. To achieve a kinematic viscosity of less than 1 10 mm2/s measured at 100°C according to ASTM D 445, the amount of Co(ll) added to the reaction mixture in the form of a Co(ll) complex is preferably 30 to 500 ppm by weight, based on the total weight of (meth)acrylic acid esters, more preferably 30 to 100 ppm by weight, most preferably 50 to 100 ppm by weight.
Suitable examples of Co(ll) complexes of the present invention include complexes comprising Co(ll) and at least one of the ligands according to formulae (II) to (VII)
Figure imgf000008_0001
Figure imgf000009_0001
wherein each R3 independently represents a phenyl group or a Ci to C12 alkyl group, or two R3 on adjacent carbon atoms together represent a C5 to Cs alkylene group; each R4 independently represents a hydrogen atom or a Ci to C12 alkyl group; each R5 independently represents a hydroxyl group or an amino group; each R6 independently represents a hydrogen atom, a Ci to C12 alkyl group, a phenyl group, a hydroxyphenyl group, or a Ci to C4 alkoxyphenyl group; and each n independently represents an integer 2 or 3. In a particularly preferred embodiment the Co(ll) complex comprises Co(ll) and a ligand of formula (VII). More preferably, the Co(ll) complex is 5,10,15,20- tetraphenyl-porphine Co(ll).
The radical initiator used in the inventive method may be any free radical initiator suitable for use in radical polymerization reactions. Such radical initiators are well known in the art. Azo compounds are particularly preferred radical initiators.
The total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight, based on the total weight of (meth)acrylic acid esters, preferably in the range of 0.1 to 3% by weight, based on the total weight of (meth)acrylic acid esters. It has surprisingly been found that by varying the amount of initiator, polymer compositions of different viscosity and different pour points may be produced. To achieve a particularly low viscosity, the total amount of initiator added to the reaction mixture is preferably 0.1 to 1 .5% by weight, based on the total weight of (meth)acrylic acid esters. The radical initiator may be added to the reaction mixture in a stepwise fashion to ensure that the radical initiator does not get depleted too quickly during long polymerization times. For example, a first dose of the radical initiator is added to the reaction mixture to start the polymerization reaction, then the reaction is allowed to proceed for a certain amount of time, then an additional dose of initiator is added, and so on. The total amount added in all steps, however, should not exceed the preferred total amount of radical initiator mentioned above. The time interval between the additions of the different doses of radical initiator may be in the range of 10 minutes to 5 hours, preferably 30 to 60 minutes.
Examples of suitable radical initiators include azo-compounds such as azobisisobutylonitrile (AIBN), 2,2'-Azobis(2-methylbutyronitrile), 2-(2-cyanobutan- 2-yldiazenyl)-2-methylbutanenitrile, and 1 ,1 -azobiscyclohexanecarbonitrile; peroxy compounds such as methyl-ethyl-ketone peroxide, acetylacetone peroxide, dilauryl peroxide, terf-butyl per-2-ethylhexaneoate, ketone peroxide, terf-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, terf-butyl peroxybenzoate, terf-butyl peroxyisopropylcarbonate, 2,5-bis- (2-ethylhexanoylperoxy)-2,5-dimethylhexane, terf-butyl peroxy-2-ethylhexanoate, terf-butyl-peroxy-3,5,5-trimethylhexanoate, dicumyl peroxide, 1 ,1 -bis(terf- butylperoxy)cyclohexane, 1 ,1 -bis(terf-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl hydroperoxide, terf-butyl hydroperoxide, and bis(4-terf-butylcyclohexyl) peroxydicarbonate; and mixtures of the aforementioned compounds.
The reaction mixture may be reacted in step d) at standard ambient pressure, reduced pressure or elevated pressure. The reaction temperature may in the range of -20°C to 200°C, preferably 50°C to 160°C, more preferably 80°C to 160°C.
In a preferred embodiment, the addition of the radical initiator in step c) and the reaction in step d) takes place in an inert gas atmosphere to prevent degradation of the radical initiator. Preferably, nitrogen gas is used as inert gas. The reaction may be allowed to proceed in step d) for up to 12 hours, preferably for 10 minutes to 12 hours, more preferably for 1 to 6 hours.
In a particularly preferred embodiment of the present invention, the method comprises the steps of:
a) preparing a reaction mixture consisting of from 0 to 60% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), having a Ci to Ce alkyl group as substituent R2, and from 40 to 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), having a C7 to C30 alkyl group as substituent R2, said (meth)acrylic acid esters according to formula (I) having a degree of linearity of at least 30% and comprising at least 20% by weight of (meth)acrylic acid esters according to formula (I) which have a C12 to C30 alkyl group as substituent R2;
b) adding Co(ll) as a catalytic chain transfer agent in the form of a complex comprising Co(ll) and a ligand according to formula (VII) at a concentration of 30 ppm to 100 ppm by weight of Co(ll), based on the total weight of (meth)acrylic acid esters;
c) adding 0.1 to 3% by weight, based on the total weight of (meth)acrylic acid esters of a radical initiator in a step-wise fashion; and
d) reacting the reaction mixture at a temperature of 80°C to 160°C for 1 to 6 hours.
In a second aspect, the present invention also relates to the use of a (meth)acrylic acid ester accordin to formula (VIII)
Figure imgf000011_0001
wherein R7 is a hydrogen atom or a methyl group, and R8 is a C12 to C30 alkyl group for the preparation of a polymer composition having a kinematic viscosity of less than 100 mm2/s, preferably less than 90 mnn2/s, more preferably less than 80 mm2/s measured at 100°C according to ASTM D 445.
In a preferred embodiment of the second aspect, R is a linear alkyl group. In another preferred embodiment, R8 is a CM to C30 alkyl group, even more preferably a linear C16 to C20 alkyl group. Preferably, the polymer composition is a composition of polymers of (meth)acrylic acid esters.
In a third aspect, the present invention relates to a method of reducing the kinematic viscosity of a polymer composition, said method comprising a method for the preparation of a polymer composition, said method for the preparation of a polymer composition comprising the steps of:
a) preparing a reaction mixture comprising a (meth)acrylic acid ester according to formula (IX) or a mixture of (meth)acrylic acid esters of formula (IX)
Figure imgf000012_0001
wherein R9 is a hydrogen atom or a methyl group, and R10 is a C7 to C30 alkyl group;
b) adding a Co(ll) complex as a catalytic chain transfer agent to the reaction mixture;
c) adding a radical initiator; and
d) reacting the reaction mixture to obtain the polymer composition,
wherein the method of reducing the kinematic viscosity is characterized in that the reaction mixture comprises
i) from 0 to 60% by weight of the (meth)acrylic acid esters of formula (IX) based on the total weight of (meth) acrylic acid esters of formula (IX) have a Ci to C6 alkyl group as substituent R10, and
ii) from 40 to 100% by weight of the (meth)acrylic acid esters of formula (IX) based on the total weight of (meth) acrylic acid esters of formula (IX) have a C7 to C30 alkyl group as substituent R10, from which at least 0.5% by weight, preferably at least 20% by weight, more preferably at least 40% by weight, most preferably 1 00% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a C12 to C30 alkyl group as substituent R10, and wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight based on the total weight of (meth)acrylic acid esters.
The method for the preparation of a polymer composition is the method to prepare a polymer composition as described above. The Co(ll) complex that is used as catalyst is the Co(ll) complex as described above.
In a preferred embodiment, at least 30% by weight, preferably at least 70% by weight, most preferably 1 00% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a linear alkyl group as substituent R10. Even more preferably, 1 00% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a linear C16 to C20 alkyl group as substituent R10.
In another preferred embodiment, at least 0.5% by weight, preferably at least 20% by weight, more preferably at least 40% by weight, most preferably 1 00% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a CM to C30 alkyl group as substituent R10.
Examples In the following examples, ethyl-hexyl methacrylate (EHMA) is a Cs methacrylate with a 0% degree of linearity. Isodecyl-methacrylate (IDMA) is a mixture consisting of 98.7% by weight Cio methacrylate, 0.8% by weight C12 methacrylate, and 0.5% by weight CM methacrylate. The degree of linearity of IDMA is approximately 0%. Methacrylate from LIAL® 125 alcohol (LIMA) is a mixture consisting of 24.3% by weight C12 methacrylate, 29.4% by weight C13 methacrylate, 28.4% by weight Ci4 methacrylate, and 17.9% by weight C15 methacrylate. The degree of linearity of LIMA is approximately 40%. Lauryl methacrylate (LMA) is a mixture consisting of 72.2% by weight C12 methacrylate, and 27.8% by weight Ci4 methacrylate. The degree of linearity of LIAL is approximately 100%.
DPMA is a mixture consisting of 24.6% by weight C12 methacrylate, 29.1 % by weight C13 methacrylate, 24.3% by weight Ci4 methacrylate, and 22.0% by weight Ci5 methacrylate. The degree of linearity of DPMA is approximately 80%.
Stearyl methacrylate (SMA) is a mixture consisting of 29.3% by weight C16 methacrylate, 69.8% by weight Cis methacrylate, and 0.8% by weight C20 methacrylate. The degree of linearity of SMA is approximately 100%.
Comparative example 1 250 g of EHMA were charged into a 500 mL 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
Example 2
250 g of IDMA were charged into a 500 ml_ 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
Example 3
250 g of LMA were charged into a 500 ml_ 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator. Example 4
250 g of LIMA were charged into a 500 ml_ 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
Example 5
250 g of DPMA were charged into a 500 ml_ 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
Example 6
250 g of SMA were charged into a 500 ml_ 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(ll) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90°C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution, composed of 25% 2-(2- cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone, was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.
Measurements of viscosity, molecular weight, and sonic shear stability
The kinematic viscosities of the polymers were measured according to ASTM D 445. The polymer molecular weights were measured by gel permeation chromatography (GPC) calibrated using PMMA standards. The sonic shear stability (SSI) was determined according to ASTM D 5621 . The pour point was determined according to ASTM D 6749. The viscosity index was determined according to ASTM D 2270.
Examples 2-6 demonstrate that the use of a cobalt based catalytic chain transfer agent for the polymerization of methacrylate monomers results in low viscosity polymers (see table 1 ), when the methacrylate monomers of the reaction mixture comprise at least 0.5 wt% (meth) acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), having a C12 to C30 alkyl group as substituent R2. The molecular weight of the polymers indicates a degree of polymerization of about 10 units.
In addition, examples 4, 5 and 6 clearly demonstrate that with an increasing degree of linearity, a lower viscosity is obtainable. Example 1 shows that when using (meth) acrylic acid esters according to formula (I), having a C7 alkyl group as substituent R2 in the reaction mixture, then polymer compositions with a kinematic viscosity of 103 mm2/s at 100°C and a molecular weight Mw of 3.2 kg/mol can be obtained. However, it was surprisingly observed that, even if Examples 1 and 2 show the lowest molecular weights Mw (3.2 kg/mol and 3.8 kg/mol, respectively), their kinematic viscosities are still higher than in Examples 3 to 6 prepared with (meth)acrylic acid esters according to formula (I), having a linear C12 to C30 alkyl group as substituent R2, despite the fact that polymer compositions of Examples 3 to 6 have much higher molecular weights Mw (4.4 kg/mol, 5.4 kg/mol, 4.9 kg/mol and 4.7 kg/mol, respectively).
Table 1 : Viscosimetric data of examples 1 to 6. The amounts given are relative to the total weight of methacrylate monomers.
Example 1 2 3 4 5 6
C7 methacrylate [% by weight] 100
Cio methacrylate [% by weight] 98.7 0
Ci2 methacrylate [% by weight] 0.8 72.2 24.3 24.6
Ci3 methacrylate [% by weight] 29.4 29.1
On methacrylate [% by weight] 0.5 27.8 28.4 24.3
Ci5 methacrylate [% by weight] 17.9 22.0
Ci6 methacrylate [% by weight] 29.3
Ci8 methacrylate [% by weight] 69.8
C20 methacrylate [% by weight] 0.8
Degree of linearity [%] 0 0 100 40 80 100
Initiator [% by weight] 0.3 0.3 0.3 0.3 0.3 0.3
Co(ll) [ppm by weight] 66 66 66 66 66 66
Mw [kg/mol] 3.2 3.8 4.4 5.4 4.9 4.7
Kinematic viscosity at 100°C [mm /s] 103 81 40 75 50 38
Kinematic viscosity at 40°C [mm /s] 2560 1746 437 1058 572 ND
Viscosity Index 109 108 140 142 144 ND
SSI (ASTM D 5621 ) 0.4 0.78 0.03 0.45 0.2 ND

Claims

Claims A method for preparing a polymer composition having a kinematic viscosity of less than 100 mm2/s measured at 100°C according to ASTM D 445, said method comprising the steps of
a) preparing a reaction mixture comprising a (meth)acrylic acid ester according to formula (I) or a mixture of (meth)acrylic acid esters of formula I)
Figure imgf000020_0001
wherein R1 is a hydrogen atom or a methyl group, and R2 is a Ci to C3o alkyl group;
b) adding a Co(ll) complex as a catalytic chain transfer agent to the reaction mixture;
c) adding a radical initiator; and
d) reacting the reaction mixture to obtain the polymer composition, characterized in that said reaction mixture comprises
i) from 0 to 60% by weight of the (meth)acrylic acid esters according to formula (I) based on the total weight of (meth) acrylic acid esters according to formula (I) have a Ci to Ce alkyl group as substituent R2, and
ii) from 40 to 100% by weight of the (meth)acrylic acid esters according to formula (I) based on the total weight of (meth) acrylic acid esters according to formula (I) have a C7 to C30 alkyl group as substituent from which at least 0.5% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth) acrylic acid esters according to formula (I), have a C12 to C30 alkyl group as substituent R2, and
wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight, based on the total weight of (meth)acrylic acid esters.
The method according to claim 1 , characterized in that at least 20% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters, have a C12 to C30 alkyl group as substituent R2.
The method according to claim 1 or 2, characterized in that at least 30% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters, have a linear alkyl group as substituent R2.
The method according to any one of the previous claims, characterized in that 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters, have a linear alkyl group as substituent R2.
The method according to claim 1 , characterized in that 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters, have a linear C12 to C30 alkyl group as substituent R2.
The method according to claim 1 , characterized in that 100% by weight of the (meth)acrylic acid esters according to formula (I), based on the total weight of (meth)acrylic acid esters, have a linear C16 to C20 alkyl group as substituent R2.
7. The method according to any one of claims 1 to 6, characterized in that the Co(ll) complex comprises Co(ll) and at least one of the ligands according to formulae (II) to (VII)
Figure imgf000022_0001
Figure imgf000023_0001
wherein each R3 independently represents a phenyl group or a Ci to C12 alkyl group, or two R3 on adjacent carbon atoms together represent a C5 to Cs alkylene group; each R4 independently represents a hydrogen atom or a Ci to C12 alkyl group; each R5 independently represents a hydroxyl group or an amino group; each R6 independently represents a hydrogen atom, a Ci to C12 alkyl group, a phenyl group, a hydroxyphenyl group, or a Ci to C4 alkoxyphenyl group; and each n independently represents an integer 2 or 3.
Figure imgf000023_0002
The method according to any one of claims 1 to 7, characterized in that the amount of Co(ll) added to the reaction mixture is 30 to 500 ppm by weight, based on the total weight of (meth)acrylic acid esters. 9. The method according to any one of claims 1 to 8, characterized in that total amount of radical initiator added to the reaction mixture is 0.1 to 3% by weight, based on the total weight of (meth)acrylic acid esters.
10. Use of a meth)acrylic acid ester according to formula (VIII)
Figure imgf000023_0003
wherein R7 is a hydrogen atom or a methyl group, and R8 is a C12 to C30 alkyl group for the preparation of a polymer composition having a kinematic viscosity of less than 100 mm2/s measured at 100°C according to ASTM D 445.
1 1 . Use of a (meth)acrylic acid ester according to claim 10, wherein R8 is a linear alkyl group.
12. A method of reducing the kinematic viscosity of a polymer composition to a kinematic viscosity of less than 100 mm2/s measured at 100°C according to ASTM D 445, said method comprising a method for preparing a polymer composition, said method for the preparation of a polymer composition comprising the steps of:
a) preparing a reaction mixture comprising a (meth)acrylic acid ester according to formula (IX) or a mixture of (meth)acrylic acid esters of formula IX)
Figure imgf000024_0001
wherein R is a hydrogen atom or a methyl group, and R is a Ci to C3o alkyl group;
b) adding a Co(ll) complex as a catalytic chain transfer agent to the reaction mixture;
c) adding a radical initiator; and
d) reacting the reaction mixture to obtain the polymer composition, wherein the method of reducing the kinematic viscosity is characterized in that
said reaction mixture comprises
i) from 0 to 60% by weight of the (meth)acrylic acid esters of formula (IX) based on the total weight of (meth) acrylic acid esters of formula (IX) have a Ci to Ce alkyl group as substituent R10, and ii) from 40 to 100% by weight of the (meth)acrylic acid esters of formula (IX) based on the total weight of (meth) acrylic acid esters of formula (IX) have a C7 to C30 alkyl group as substituent R10,
from which at least 0.5% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a C12 to C30 alkyl group as substituent R10, and
wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight based on the total weight of (meth)acrylic acid esters of formula (IX).
A method according to claim 12, characterized in that at least 30% by weight of the (meth)acrylic acid esters according to formula (IX), based on the total weight of (meth) acrylic acid esters according to formula (IX), have a linear alkyl group as substituent R10.
PCT/EP2013/077336 2013-01-04 2013-12-19 Preparation of low-viscosity polymers WO2014106589A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201361748941P 2013-01-04 2013-01-04
US61/748,941 2013-01-04
EP13152969.5 2013-01-29
EP13152969 2013-01-29

Publications (1)

Publication Number Publication Date
WO2014106589A1 true WO2014106589A1 (en) 2014-07-10

Family

ID=47605404

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/077336 WO2014106589A1 (en) 2013-01-04 2013-12-19 Preparation of low-viscosity polymers

Country Status (1)

Country Link
WO (1) WO2014106589A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4321602A1 (en) 2022-08-10 2024-02-14 Evonik Operations GmbH Sulfur free poly alkyl(meth)acrylate copolymers as viscosity index improvers in lubricants

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0861859A2 (en) * 1997-02-27 1998-09-02 Rohm And Haas Company Process for preparing continuously variable-composition copolymers
WO2001040317A2 (en) * 1999-11-30 2001-06-07 Rohmax Additives Gmbh Method for producing a liquid polymer composition and the use of this composition
WO2001040333A1 (en) * 1999-11-30 2001-06-07 Rohmax Additives Gmbh Gradient copolymers and method for the production thereof and their use
DE10314776A1 (en) * 2003-03-31 2004-10-14 Rohmax Additives Gmbh Lubricating oil composition with good rubbing properties
WO2008058774A1 (en) * 2006-11-13 2008-05-22 Evonik Rohmax Additives Gmbh Improvement in quality control of a functional fluid
WO2010043503A1 (en) * 2008-10-14 2010-04-22 Evonik Rohmax Additives Gmbh Hydraulic fluid composition that reduces hydraulic system noise
WO2012076676A1 (en) * 2010-12-10 2012-06-14 Evonik Rohmax Additives Gmbh A viscosity index improver comprising a polyalkyl(meth)acrylate polymer

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0861859A2 (en) * 1997-02-27 1998-09-02 Rohm And Haas Company Process for preparing continuously variable-composition copolymers
WO2001040317A2 (en) * 1999-11-30 2001-06-07 Rohmax Additives Gmbh Method for producing a liquid polymer composition and the use of this composition
WO2001040333A1 (en) * 1999-11-30 2001-06-07 Rohmax Additives Gmbh Gradient copolymers and method for the production thereof and their use
DE10314776A1 (en) * 2003-03-31 2004-10-14 Rohmax Additives Gmbh Lubricating oil composition with good rubbing properties
WO2008058774A1 (en) * 2006-11-13 2008-05-22 Evonik Rohmax Additives Gmbh Improvement in quality control of a functional fluid
WO2010043503A1 (en) * 2008-10-14 2010-04-22 Evonik Rohmax Additives Gmbh Hydraulic fluid composition that reduces hydraulic system noise
WO2012076676A1 (en) * 2010-12-10 2012-06-14 Evonik Rohmax Additives Gmbh A viscosity index improver comprising a polyalkyl(meth)acrylate polymer

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
J. P. A. HEUTS, D. J. FORSTER, T. P. DAVIS: "Reversible cobalt -carbon bond formation in catalytic chain transfer polymerization", MACROMOLECULES, vol. 32, 31 March 1999 (1999-03-31), pages 2511 - 2519, XP002723331 *
J. P. A. HEUTS, D. J. FORSTER, T. P. DAVIS: "The effects of ester chain length and temperature on the catalytic chain transfer polymerization of methacrylates", MACROMOLECULES, vol. 32, 27 May 1999 (1999-05-27), pages 3907 - 3912, XP002723332 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4321602A1 (en) 2022-08-10 2024-02-14 Evonik Operations GmbH Sulfur free poly alkyl(meth)acrylate copolymers as viscosity index improvers in lubricants

Similar Documents

Publication Publication Date Title
JP5021303B2 (en) Lubricating oil additive and lubricating oil composition containing acrylic polymer
CN102770470B (en) A polymer useful as viscosity index improver
KR102380697B1 (en) Gradient copolymer, preparation method and use thereof
KR100405388B1 (en) Multifunctional additive for lubricants compatible with fluoroelastomer
US20230063756A1 (en) Polymer Composition, Lubricant Additive, Viscosity Index Improver, Lubricant Composition, Method for Producing Polymer Composition, and Method for Producing Macromonomer
EP4007782A1 (en) Lipophylic copolymers comprising polar multi-blocks, process for the preparation thereof and use in lubricating compositions
JP6752793B2 (en) Method for producing copolymer of alkyl methacrylate and maleic anhydride
CA2162552C (en) Dispersant viscosity index improving additive for lubricating oils
WO2014106589A1 (en) Preparation of low-viscosity polymers
US9580529B2 (en) Preparation of low-viscosity polymers
KR20150082242A (en) Process for preparing low sulfur dispersant polymers
JP3541081B2 (en) Method for producing copolymer with improved viscosity index
RU2402571C1 (en) Method of producing polymethacrylate pour-point depressant and pour-point depressant obtained using said method
WO2014105290A1 (en) Alternating block copolymer and process for making
JP2022157579A (en) Polymer, production method of polymer, lubricant additive and lubricant
JP2017160310A (en) Viscosity index improver and lubricant composition

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13811517

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13811517

Country of ref document: EP

Kind code of ref document: A1