阅读说明：本技术 一种用于润滑油的星形分散型黏度指数改进剂及其制备方法 (Star-shaped dispersion type viscosity index improver for lubricating oil and preparation method thereof ) 是由 李嵬 胥维昌 鄂彦鹏 沈照千 刘晓杰 陈二中 卢俊典 于 2019-10-29 设计创作，主要内容包括：本发明涉及一种用于润滑油的星形分散型黏度指数改进剂及其制备方法。该黏度指数改进剂为星形胺基官能化氢化苯乙烯-双烯共聚物,所述分散型黏度指数改进剂的氢化前体的结构为：(ω-end-DPE-(NR<Sub>2</Sub>)<Sub>m</Sub>/SIB)<Sub>n</Sub>-C或(in-DPE-(NR<Sub>2</Sub>)<Sub>m</Sub>/SIB)<Sub>n</Sub>-C,星形黏度指数改进剂的总数均分子量为5×10<Sup>4</Sup>-8×10<Sup>5</Sup>,臂数均分子量为1×10<Sup>4</Sup>-1×10<Sup>5</Sup>,分子量分布为1.0-1.5,按照质量百分比,苯乙烯单元的含量占0-40％,异戊二烯单元的含量占30-90％,丁二烯单元的含量占0-50％,每条聚合物臂上含有1-20个胺基基团。本发明的分散型黏度指数改进剂为兼具分散和黏度指数改进双重功能的添加剂,具有优异的烟炱分散性、增稠能力和剪切稳定性,有效降低分散剂用量或无需使用分散剂。(The invention relates to a star-shaped dispersion viscosity index improver for lubricating oil and a preparation method thereof. The viscosity index improver is star-amino functionalized hydrogenated styrene-diene copolymer, and the dispersive viscosity index improverThe structure of the hydrogenation precursor of the promoter is: (omega-end-DPE- (NR) 2 ) m /SIB) n -C or (in-DPE- (NR) 2 ) m /SIB) n C, total number average molecular weight of star viscosity index improver 5X 10 4 ‑8×10 5 Arm number average molecular weight of 1X 10 4 ‑1×10 5 The molecular weight distribution is 1.0-1.5, according to the mass percentage, the content of styrene units accounts for 0-40%, the content of isoprene units accounts for 30-90%, the content of butadiene units accounts for 0-50%, and each polymer arm contains 1-20 amido groups. The dispersion type viscosity index improver is an additive with dual functions of dispersion and viscosity index improvement, has excellent soot dispersibility, thickening capability and shear stability, and effectively reduces the using amount of a dispersant or does not need to use the dispersant.)

1. A star-shaped dispersion type viscosity index improver for lubricating oil is characterized in that: the star-shaped dispersion viscosity index improver is star-shaped amino functionalized hydrogenated styrene-diene copolymer, and the total number average molecular weight of the star-shaped viscosity index improver is 5 multiplied by 10⁴-8×10⁵Arm number average molecular weight of 1X 10⁴-1×10⁵The molecular weight distribution is 1.0-1.5, according to the mass percentage, the content of styrene unit accounts for 0-40%, the content of isoprene unit accounts for 30-90%, the content of butadiene unit accounts for 0-50%, and each polymer arm contains 1-20 amido groups; the structure of the hydrogenated precursor of the copolymer is: (omega-end-DPE- (NR)₂)_m/SIB)_n-C or (in-DPE- (NR)₂)_m/SIB)_n-C。

2. A star dispersant viscosity index improver for lubricating oils according to claim 1, wherein: the structure of the hydrogenated precursor of the copolymer is: chain-end functionalized Star polymers (. omega. -end-DPE- (NR)₂)_m/SIB)_n-C-or in-chain functionalized Star polymers (in-DPE- (NR)₂)_m/SIB)_n-C, wherein: SIB is ternary copolymer segment of styrene (S), isoprene (I) and butadiene (B), C is polydivinylbenzene residue, omega-end-DPE- (NR)₂)_mThe amine-functionalized DPE monomer of (a) is linked at the end of the star polymer chain, in-DPE- (NR)₂)_mThe amine-functionalized DPE monomers of (a) are linked in the star polymer chain, R is methyl or ethyl, m is the number of linked functionalized groups per DPE, m is 1 or 2, n is the average number of arms of the star polymer, and n is a natural number from 2 to 15.

3. The star dispersion viscosity index improver for lubricating oils according to claim 2, characterized in that: s in the SIB segment in the hydrogenated precursor accounts for 1-40% of the total monomer mass, I accounts for 20-100% of the total monomer mass, and B accounts for 1-60% of the total monomer mass.

4. A method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 1, wherein:

a: mixing styrene, isoprene and butadiene as total monomer with polar additive, adding into nonpolar hydrocarbon solvent, stirring, and adding into aminoLithium initiator of functionalized compound, and polymerizing at 20-90 deg.c to obtain chain end amino functionalized SIB random copolymer (omega-end-DPE- (NR)₂)_m/SIB); wherein the mass ratio of the total monomers to the nonpolar hydrocarbon solvent is 1: 3-20; the addition amount of alkyl lithium is 1X 10^-3-1×10^-2mol per 100g total monomer, the molar ratio of polar additive to alkyl lithium is 0-40: 1;

or, taking styrene, isoprene and butadiene as total monomers, adding the monomers and amino functionalized DPE or the monomers and amino functionalized compound and polar additive into a nonpolar hydrocarbon solvent, stirring uniformly, adding alkyl lithium, and carrying out polymerization reaction at 20-90 ℃ to obtain the chain amino functionalized SIB random copolymer (in-DPE- (NR)₂)_m/SIB); wherein the mass ratio of the total monomers to the nonpolar hydrocarbon solvent is 1: 3-20; the lithium initiator is added in an amount of 1X 10^-3-1×10^-2mol per 100g total monomer, the molar ratio of polar additive to lithium initiator is 0-40: 1;

b: adding a coupling agent into the obtained amino-functionalized SIB random copolymer system to react at 20-90 ℃, adding isopropanol into the system to terminate the coupling reaction when the conversion rate of the coupling agent exceeds 95%, and obtaining a hydride precursor, namely the chain-end functionalized star polymer (omega-end-DPE- (NR)₂)_m/SIB)_n-C-or in-chain functionalized Star polymers (in-DPE- (NR)₂)_m/SIB)_n-C; wherein the molar ratio of the coupling agent to the alkyl lithium is 1-30: 1;

c: adding a hydrogenation catalyst into the precursor, uniformly mixing, introducing hydrogenation, carrying out hydrogenation reaction at the temperature of 10-80 ℃ and the hydrogen pressure of 1.0-6.0MPa, and removing the hydrogenation catalyst after reaction to obtain the chain-end or chain-middle amino functionalized star-shaped dispersed viscosity index improver.

5. The method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 4, wherein: the nonpolar hydrocarbon solvent is one or two of n-hexane, cyclohexane, xylene, toluene, ethylbenzene, pentane, heptane, octane or raffinate oil.

6. The method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 4, wherein: the molecular formula of the alkyl lithium is RLi, R is C₄-C₂₀Alkyl group of (1).

7. The method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 3, wherein: the polar additive is one or more of oxygen-containing polar compounds, nitrogen-containing polar compounds or alkoxy metal compounds.

8. A polar additive according to claim 7, characterized in that: the oxygen-containing polar additive is diethyl ether, tetrahydrofuran, R₁OCH₂CH₂OR₂、R₁OCH₂CH₂OCH₂CH₂OR₂Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether or diethylene glycol diethyl ether; wherein R is₁、R₂Identical or different from C₁-C₆Alkyl groups of (a);

the nitrogen polar compound is tetramethyl ethylene diamine, triethylamine or dipiperidine ethane;

the metal alkoxide compound is ROM, wherein R is C₁-C₁₀Alkyl or C₆-C₂₀O is an oxygen atom, and M is Na or K.

9. The method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 3, wherein: the coupling agent is an epoxy compound or a diene compound.

10. The method of preparing a star dispersant viscosity index improver for lubricating oils according to claim 3, wherein: the hydrogenation reaction ensures that the hydrogenation degree of unsaturated double bonds of diolefin in the copolymer is more than 95 percent, the hydrogenation degree of unsaturated bonds of aromatic hydrocarbon is less than 10 percent, and the residual quantity of the catalyst is less than 30 ppm.

Technical Field

The invention relates to a star-shaped dispersion type viscosity index improver for lubricating oil, in particular to a star-shaped dispersion type hydrogenated styrene-diene copolymer viscosity index improver and a preparation method thereof.

Background

With the automation and integration of automobile engines, the requirements for engine oil are becoming more and more demanding. Especially, with the adoption of new technologies, such as a fuel delay injection technology, a turbocharging technology, an exhaust gas recirculation technology and the like, soot is generated in the combustion process of fuel, and if the soot is not effectively dispersed, the lubricating effect of an oil product is rapidly deteriorated, so that the service life of the oil product is greatly reduced. Not only increases the burden of consumers, but also can cause the damage of the engine when the load is serious. There are generally two approaches to solving the soot dispersion problem: one is adding dispersant into engine oil; one is to add additives with dispersant properties, such as dispersant viscosity index improvers, to the engine oil. The addition of a dispersion-type viscosity index improver has been widely adopted because of the great reduction in production cost. The dispersive viscosity index improver mainly comprises two types: a dispersion type ethylene-propylene viscosity index improver and a dispersion type hydrogenated styrene-diene copolymer viscosity index improver.

U.S. Pat. No. 4,41847 discloses a dispersed hydrogenated styrene diene copolymer viscosity index improver, which is obtained by reacting a hydrogenated styrene diene copolymer with an alpha-beta unsaturated acid or anhydride and then with an amine. US patent 4077893 discloses a similar viscosity index improver, except that a polyol is used instead of an amine. The synthesis processes of the two viscosity index improvers have the same defect that both comprise a free radical reaction process and a condensation reaction process, the two processes are carried out at high temperature (the free radical reaction is 140 ℃, the condensation reaction is 180-250 ℃), the energy consumption is increased, and the products are easy to generate side reactions such as crosslinking, degradation and the like, so that the product performance is seriously influenced.

Chinese patent CN106336490B discloses a dispersed hydrogenated styrene diene copolymer viscosity index improver, wherein the dispersed hydrogenated styrene diene copolymer is coupled with DVB and then added with 2-vinylpyridine or 4-vinylpyridine to obtain the dispersed hydrogenated styrene diene copolymer viscosity index improver. The viscosity index improver contains a nitrogen functional group at the position of a star polymer core, and the steric effect of a star polymer arm reduces the dispersing performance of the nitrogen functional group.

Disclosure of Invention

The invention aims to provide a star-shaped dispersion type hydrogenated styrene-diene copolymer viscosity index improver for lubricating oil and a preparation method thereof.

In order to realize the purpose, the technical scheme is as follows:

a star-shaped dispersing viscosity index improver for lubricating oil is a starlike amino functionalized hydrogenated styrene-diene copolymer, and has a total number average molecular weight of 5 × 10⁴-8×10⁵Arm number average molecular weight of 1X 10⁴-1×10⁵The molecular weight distribution is 1.0-1.5, the content of styrene unit is 0-40% according to the mass percentage, the isoprene monomerThe content of the component is 30-90%, the content of the butadiene unit is 0-50%, and each polymer arm contains 1-20 amido groups; the structure of the hydrogenated precursor of the copolymer is: (omega-end-DPE- (NR)₂)_m/SIB)_n-C or (in-DPE- (NR)₂)_m/SIB)_n-C。

The structure of the hydrogenated precursor of the copolymer is: chain-end functionalized Star polymers (. omega. -end-DPE- (NR)₂)_m/SIB)_n-C-or in-chain functionalized Star polymers (in-DPE- (NR)₂)_m/SIB)_n-C, wherein: SIB is ternary copolymer segment of styrene (S), isoprene (I) and butadiene (B), C is polydivinylbenzene residue, omega-end-DPE- (NR)₂)_mThe amine-functionalized DPE monomer of (a) is linked at the end of the star polymer chain, in-DPE- (NR)₂)_mThe amine-functionalized DPE monomers of (a) are linked in the star polymer chain, R is methyl or ethyl, m is the number of linked functionalized groups per DPE, m is 1 or 2, n is the average number of arms of the star polymer, and n is a natural number from 2 to 15.

S in the SIB segment in the hydrogenated precursor accounts for 1-40% of the total monomer mass, I accounts for 20-100% of the total monomer mass, and B accounts for 1-60% of the total monomer mass.

The hydrogenation precursor has isoprene units and butadiene monomers with a hydrogenation degree of more than 95% and styrene units with a hydrogenation degree of less than 10%.

Due to the introduction of an amine-functional monomer DPE- (NR) in the chain or at the chain end of the polymer₂)_mThe purpose of controlling the number and the position of the amino functionalized monomer in the star polymer is realized, and the controllability of the dispersion performance of the viscosity index improver is further realized.

The mid-chain or end-chain amine functionalized star viscosity index improvers of the present invention have higher, more controllable dispersancy performance than non-functionalized non-dispersible star viscosity index improvers and core functionalized weakly dispersible star viscosity index improvers.

A preparation method of a star-shaped dispersion type viscosity index improver for lubricating oil comprises the following steps:

a: mixing styreneIsoprene and butadiene as total monomers, mixing with polar additive, adding into nonpolar hydrocarbon solvent, stirring, adding lithium initiator of amino-functionalized amino compound, and performing polymerization at 20-90 deg.C to obtain chain-end amino-functionalized SIB random copolymer (omega-end-DPE- (NR)₂)_m/SIB)；

The lithium initiator of the amino functional compound is prepared by premixing and aging the amino functional compound and alkyl lithium; the amine-functional compound is DPE- (NR)₂)_mPreferably, it is a mono-or di-amine functionalized DPE. The monomer is synthesized by converting relevant benzophenone derivatives into stilbene derivatives through one-step Wittig reaction under anhydrous and oxygen-free conditions.

Wherein the mass ratio of the total monomers to the nonpolar hydrocarbon solvent is 1: 3-20; the addition amount of alkyl lithium is 1X 10^-3-1×10^-2mol per 100g total monomer, the molar ratio of polar additive to alkyl lithium is 0-40: 1; alkyl lithium, preferably n-butyl lithium and sec-butyl lithium.

Or, taking styrene, isoprene and butadiene as total monomers, adding the monomers and amino functionalized DPE or adding the monomers and amino functionalized amino compound and polar additive into a nonpolar hydrocarbon solvent, stirring uniformly, adding alkyl lithium, and carrying out polymerization reaction at 20-90 ℃ to obtain the chain amino functionalized SIB random copolymer (in-DPE- (NR)₂)_m/SIB); wherein the mass ratio of the total monomers to the nonpolar hydrocarbon solvent is 1: 3-20; the lithium initiator is added in an amount of 1X 10^-3-1×10^{- 2}mol per 100g total monomer, the molar ratio of polar additive to lithium initiator is 0-40: 1;

in the step A, the polar additive in the system can be added or not added;

b: adding a coupling agent into the obtained amino-functionalized SIB random copolymer system to react at 20-90 ℃, adding isopropanol into the system to terminate the coupling reaction when the conversion rate of the coupling agent exceeds 95%, and obtaining a hydride precursor, namely the chain-end functionalized star polymer (omega-end-DPE- (NR)₂)_m/SIB)_n-C-or in-chain functionalized Star polymers (in-DPE- (NR)₂)_m/SIB)_n-C; wherein the molar ratio of the coupling agent to the alkyl lithium is 1-30: 1; addition amount of isopropyl alcohol: the molar ratio to alkyllithium is 1: 1;

c: adding a hydrogenation catalyst into the precursor, uniformly mixing, introducing hydrogenation, carrying out hydrogenation reaction at the temperature of 10-80 ℃ and the hydrogen pressure of 1.0-6.0MPa, and removing the hydrogenation catalyst after reaction to obtain the chain-end or chain-middle amino functionalized star-shaped dispersed viscosity index improver.

The hydrogenation of the polymer in step C) may be carried out by any suitable hydrogenation process, the hydrogenation catalyst comprising a non-noble metal or non-noble metal-containing compound of group VIII of the periodic Table (i.e., iron, cobalt, nickel, especially nickel). Specifically, triisobutyl aluminum and nickel naphthenate are mixed and aged at 50-70 ℃, and the aged mixture is used as a hydrogenation catalyst and added into a reaction system, wherein the main catalyst is nickel naphthenate: 0.2-10mg nickel per gram polymer; the amount of triisobutylaluminum as cocatalyst is as follows: the molar ratio of triisobutylaluminum to nickel naphthenate is 2-8: 1.

The nonpolar hydrocarbon solvent is one or two of n-hexane, cyclohexane, xylene, toluene, ethylbenzene, pentane, heptane, octane or raffinate oil. Preferably: cyclohexane.

The molecular formula of the alkyl lithium is RLi, R is C₄-C₂₀Alkyl group of (1). N-butyllithium or sec-butyllithium is preferred.

The polar additive is one or more of oxygen-containing polar compounds, nitrogen-containing polar compounds or alkoxy metal compounds. Preferably: an oxygen-containing polar additive;

the oxygen-containing polar additive is diethyl ether, tetrahydrofuran, R₁OCH₂CH₂OR₂、R₁OCH₂CH₂OCH₂CH₂OR₂Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether or diethylene glycol diethyl ether; wherein R is₁、R₂Identical or different from C₁-C₆Alkyl groups of (a); preferably: tetrahydrofuran;

the nitrogen polar compound is tetramethyl ethylene diamine, triethylamine or dipiperidine ethane; preferably: tetramethylethylenediamine;

the metal alkoxide compound is ROM, wherein R is C₁-C₁₀Alkyl or C₆-C₂₀O is an oxygen atom, and M is Na or K. Potassium tert-butoxide or potassium tert-pentoxide are preferred.

The coupling agent is an epoxy compound or a diene compound. The diene compound is Divinylbenzene (DVB) and 1, 3-distyrylbenzene; the epoxy compound is epoxidized soybean oil or epoxidized linseed oil.

The amine-functional compound is preferably a mono-amine-functional DPE or a di-amine-functional DPE.

The adding mode of the coupling agent is one-time addition, multiple addition or continuous addition.

The hydrogenation reaction ensures that the hydrogenation degree of unsaturated double bonds of diolefin in the copolymer is more than 95 percent, the hydrogenation degree of unsaturated bonds of aromatic hydrocarbon is less than 10 percent, and the residual quantity of the catalyst is less than 30 ppm; the catalyst is a ziegler-natta type catalyst, preferably nickel naphthenate and triisobutylaluminum.

The star-shaped dispersion viscosity index improver has the following advantages:

the modifier has excellent soot dispersibility, tackifying capability, oxidation resistance, shear stability and dispersibility, and the delta V of the lubricating oil containing the star-shaped dispersed viscosity index improver provided by the invention_kThe values are significantly lower and therefore the viscosity index improver of the present invention has excellent dispersancy of soot in lubricating oils.

Detailed Description

The present invention will be described in further detail with reference to examples, which should not be construed as limiting the invention thereto.

The characterization method comprises the following steps:

1. microstructure and nitrogen content of the product¹H NMR，¹³C NMR, and the molecular weight of the polymer and its distribution by GPC.

2. The performance test of the product comprises the following steps: the standard for testing the tackifying ability is SH/T0566-93; the method standard for testing shear stability is SH/T0103-92.

3. The dispersion performance of the product is evaluated by adopting a carbon black dispersion method, specifically, a watch glass containing a carbon black sample is placed in a drying oven at 120 ℃ for drying for 12 hours, and is naturally cooled to room temperature; the product is added into HVI H5 base oil according to the proportion of 5 percent, 7 percent of dispersant T151A is added at the same time, and the mixture is stirred and dissolved at the temperature of 60-80 ℃: adding carbon black into the oil product according to the proportion of 2 percent, and dispersing for 30 minutes by a high-speed dispersion homogenizer at the rotating speed of 10000 rpm; after the sample has been dispersed, the viscosity at 60 ℃ is measured rapidly using a previously preheated viscometer, the percentage increase in viscosity being greater than the viscosity before the addition of carbon black, using Δ V_kAnd (4) showing.