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CN-122011266-A - Polymethacrylate type hydraulic oil viscosity index improver and preparation method thereof

CN122011266ACN 122011266 ACN122011266 ACN 122011266ACN-122011266-A

Abstract

The invention belongs to the technical field of hydraulic oil, and particularly relates to a polymethacrylate type hydraulic oil viscosity index improver and a preparation method thereof. By adopting ultraviolet light assisted initiation with specific wavelength (200-400 nm, preferably 254 nm or 365 nm), side reactions such as thermal degradation and oxidation caused by high temperature in the traditional thermal polymerization process are obviously inhibited. The ultraviolet light is utilized to initiate the combined dripping process to maintain the relative stability of the monomer concentration, so that the chain growth reaction is more stable and uniform. Under the regular polymerization structure initiated by ultraviolet light, the copolymerization of methacrylic acid C1-C4, C5-C12, C13-C24 alkyl ester monomers and olefin monomers with specific molar ratio generates obvious synergistic effect. The structure not only significantly reduces the pour point (up to-52 ℃) and low temperature viscosity (KV-18) of hydraulic oil through the effective accommodation of long-chain alkyl ester, but also enhances the mechanical shearing resistance of the polymer through the regular chain structure.

Inventors

  • LI KE
  • XIAO QI
  • ZHAO ZHONGYUAN
  • PENG FENG
  • ZHAO XUHE

Assignees

  • 新乡市瑞丰新材料股份有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. The preparation method of the polymethacrylate hydraulic oil viscosity index improver is characterized by comprising the following steps of: S1, adding base oil into a reaction device and heating; S2, uniformly mixing a C1-C4 alkyl methacrylate monomer, a C5-C12 alkyl methacrylate monomer and a C13-C24 alkyl methacrylate monomer with 4/5 molecular chain transfer agent and 4/5 initiator to obtain a mixture A, and uniformly mixing an olefin monomer with 4/5 molecular chain transfer agent and 4/5 initiator to obtain a mixture B; s3, dropwise adding the mixture A and the mixture B obtained in the step S2 into the heated base oil under the stirring condition, and simultaneously irradiating with ultraviolet light with the wavelength of 254nm or 365nm to perform copolymerization reaction; And S4, after the reaction is finished, cooling to obtain the polymethacrylate hydraulic oil viscosity index improver.
  2. 2. The method according to claim 1, wherein the molar ratio of the C1-C4 alkyl methacrylate monomer, the C5-C12 alkyl methacrylate monomer, the C13-C24 alkyl methacrylate monomer to the olefin-based monomer in S2 is 1 (1-8): (0.3-5): (0.01-3).
  3. 3. The method according to claim 2, wherein the molar ratio of the C1-C4 alkyl methacrylate monomer, the C5-C12 alkyl methacrylate monomer, the C13-C24 alkyl methacrylate monomer to the olefin-based monomer is 1 (1-6): 0.3-4): 0.05-2.
  4. 4. The method according to claim 3, wherein the molar ratio of the C1-C4 alkyl methacrylate monomer, the C5-C12 alkyl methacrylate monomer, the C13-C24 alkyl methacrylate monomer to the olefin monomer is 1 (1-4): 0.3-2): 0.1-1.
  5. 5. The process according to any one of claims 1 to 4, wherein in S2, the olefin monomer is one or more selected from the group consisting of styrene, low molecular weight polyisobutylene and vinyl acetate, and the low molecular weight polyisobutylene has a molecular weight of 300 to 1300.
  6. 6. The process according to any one of claims 1 to 4, wherein in S2, the initiator is t-butyl peroxyoctoate, t-butyl peroxy-2-ethylhexanoate or t-butyl peroxybenzoate, added in an amount of 1 to 4% of the total mass of the alkyl ester monomer; The molecular chain transfer agent is one or more selected from 2, 4-diphenyl-4-methyl-1-pentene, n-dodecyl mercaptan and tert-dodecyl mercaptan, and the addition amount of the molecular chain transfer agent is 0.5-5% of the total mass of the alkyl ester monomer.
  7. 7. The process according to claim 6, wherein the initiator is selected from t-butyl peroxy-2-ethylhexanoate in an amount of 1.5-2% of the total mass of the monomer mixture; the addition amount of the molecular chain transfer agent is 1-3%.
  8. 8. The method according to claim 1, wherein in step S3, the copolymerization is carried out at a temperature of 85-130 ℃ for a reaction time of 2-8 hours, preferably 3-6 hours, and the dropwise addition time is 0.5-8 hours, preferably 3-6 hours.
  9. 9. The method of claim 1, wherein in step S1, the base oil is a hydrogenated base oil, the mass of which is 20-50%, preferably 35-45% of the total mass of the monomer mixture.
  10. 10. A polymethacrylate type hydraulic oil viscosity index improver prepared by the preparation method according to any one of claims 1 to 9.

Description

Polymethacrylate type hydraulic oil viscosity index improver and preparation method thereof Technical Field The invention belongs to the technical field of hydraulic oil, and particularly relates to a polymethacrylate type hydraulic oil viscosity index improver and a preparation method thereof. Background The viscosity index improver (Viscosity Index Improvers, VII) is a high-molecular polymer additive capable of obviously improving viscosity-temperature characteristics of lubricating oil, and has the core function of reducing the influence of temperature change on the viscosity of the lubricating oil, so that the effective working temperature range of the lubricating oil is enlarged. In a hydraulic system, the function of the viscosity index improver is particularly critical, and the viscosity index improver can ensure that hydraulic oil keeps good fluidity under low-temperature conditions, and simultaneously maintains enough oil film thickness under high-temperature conditions, so that the viscosity index improver has great significance for stable operation of the hydraulic system, reduction of abrasion and extension of equipment life. In recent years, the development of hydraulic technology, the technical upgrading of hydraulic parts and equipment working conditions (such as engineering machinery) are increasingly harsh, and environmental protection requirements are continuously upgraded, so that on the basis of meeting the related current national and international standards of hydraulic oil, markets and users have higher and more specific requirements on the hydraulic oil, and the direction is pointed out for the development of new technology and new requirements of the hydraulic oil in the next few years. The oil-using requirements of a plurality of engineering machinery manufacturers on the oil-using requirements of equipment such as an excavator and the like are higher, and the requirements can be met by adopting a low-dosage and high-shear-stability adhesive. Polymethacrylates (PMA) are one of the most widely used non-dispersed viscosity index improvers. By changing the length and structure of the ester side chain, the solubility, thickening ability and low temperature performance of the ester side chain in the base oil can be adjusted. Traditional PMA adhesives are usually prepared by adopting a thermal-initiated free radical polymerization process, and the process is mature, but the following technical bottlenecks to be solved are still faced in practical application: 1. Thermally initiated polymerizations typically need to be carried out at relatively high temperatures (e.g., >100 ℃) for long periods of time, are prone to initiate side reactions such as thermal oxidation, degradation, etc. of monomers and polymers, lead to darkening of the final product (high color number), affect product appearance quality and market competitiveness, and may introduce unstable chemical components. 2. The traditional thermal polymerization process has relatively poor controllability, and is easy to lead to the over wide molecular weight distribution of the polymer. In a widely distributed polymer, too long molecular chains are subject to breakage under mechanical shear, resulting in permanent viscosity loss (i.e., poor shear stability), while too short molecular chains have low thickening efficiency. This makes it difficult to achieve stability and optimization of product properties, especially shear sensitive properties. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide the polymethacrylate type hydraulic oil viscosity index improver and the preparation method thereof, so that the chromaticity of products can be synchronously improved, the molecular structure can be precisely controlled, the thickening efficiency, the low-temperature performance and the shear stability of the product can be fundamentally and cooperatively improved, and the development requirement of high-end hydraulic oil can be met. In order to achieve the above purpose, the present invention adopts the following technical scheme: 1. the preparation method of the polymethacrylate hydraulic oil viscosity index improver is characterized by comprising the following steps of: S1, adding base oil into a reaction device and heating; S2, uniformly mixing a C1-C4 alkyl methacrylate monomer, a C5-C12 alkyl methacrylate monomer and a C13-C24 alkyl methacrylate monomer with 4/5 molecular chain transfer agent and 4/5 initiator to obtain a mixture A, and uniformly mixing an olefin monomer with 4/5 molecular chain transfer agent and 4/5 initiator to obtain a mixture B; s3, dropwise adding the mixture A and the mixture B obtained in the step S2 into the heated base oil under the stirring condition, and simultaneously irradiating with ultraviolet light with the wavelength of 254nm or 365nm to perform copolymerization reaction; And S4, after the reaction is finished, cooling to obtain the polymethacrylate