In-situ polymerization type acrylate-organosilicon composite silicone grease and preparation method thereof

Abstract

The invention discloses in-situ polymerization type acrylate-organic silicon composite silicone grease and a preparation method thereof, and relates to the technical field of organic silicon materials and polymer modification. Polyorganosiloxane is adopted to construct a thixotropic silicone grease matrix, in-situ polymerization is combined to prepare a silicon-containing acrylate copolymer P, and then the silicon-containing acrylate copolymer P is stably integrated into a silicone grease network in a deep compounding mode. According to the composite structure, the compatibility and storage stability with oil paint and ink systems are remarkably improved, and component migration and precipitation are effectively inhibited; meanwhile, the defoaming agent also has obvious advantages in the aspects of defoaming and foam inhibition performance, and especially can efficiently eliminate micron-sized micro bubbles which are difficult to remove in a system, so that the surface quality of a coating film is improved, and the compactness and the protection performance of the coating layer are improved. The acrylate modified organic silicon R is introduced, and a homogenization treatment process is combined, so that the microstructure of the composite silicone grease is more uniform and compact, and the application range of the composite silicone grease in oil paint, printing ink and other multi-phase industrial systems is widened.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon materials and polymer modification technology, specifically relating to an acrylate-organosilicon composite silicone grease prepared by solution copolymerization-compounding of silicone acrylate copolymers or in-situ polymerization of silicone grease medium using silicone grease as a carrier, and its preparation method. Background Technology

[0002] In recent years, with the country's increasing emphasis on environmental protection, water-based coatings are gradually replacing traditional oil-based coatings in various application areas, especially in the home decoration market. However, oil-based coatings, with their excellent waterproof, anti-corrosion, wear-resistant, and durable properties, still occupy an irreplaceable position in fields with stringent protective requirements, such as construction, machinery manufacturing, railways, ships, and aerospace. In the construction field, oil-based coatings are widely used for waterproofing and moisture-proofing of building exteriors, roofs, and walls, and can also be used as fire-retardant coatings; the dense protective film they form can effectively block or delay the damage to the substrate by corrosive media such as moisture and oxygen, significantly extending the service life of building structures. In addition, oil-based coatings are also used in special environments such as underground engineering and water conservancy projects, further highlighting their key role in high-performance protective systems.

[0003] In the production and application of oil-based coatings, the introduction of air bubbles is unavoidable, affecting not only the appearance of the coating film but also potentially weakening its physical properties and protective effects. Therefore, defoamers are indispensable additives. Currently, commercially available defoamers are mainly classified by chemical composition into mineral oil-based, polyether-based, silicone-based, and polyacrylate-based defoamers. Among them, mineral oil defoamers have good compatibility, high addition tolerance, and are less likely to cause pinholes; polyether-based defoamers have excellent foam suppression performance but generally moderate defoaming ability; silicone-based defoamers have high defoaming efficiency but generally suffer from poor foam suppression; polyacrylate-based defoamers show a balance between defoaming power and compatibility, but their foam suppression performance is still inferior to polyether-based defoamers. To balance defoaming efficiency, foam suppression durability, and system compatibility, the industry has developed various modified silicone defoamers in recent years, such as polyether-modified silicone and fluorine-modified silicone. However, these modified products still have significant shortcomings in eliminating micron-sized microbubbles and compatibility with complex polar systems, making it difficult to meet the stringent requirements of high-end oil-based coatings for surface quality and long-term stability.

[0004] It is worth noting that some high-performance defoaming systems (especially silicone-based ones) often use silicone grease as a carrier or functional component. Silicone grease is usually formed by high-shear dispersion of silicone oil and reinforcing fillers (such as fumed silica) to form a thick gel system, and silicone resins (such as MQ resin) can be further introduced to enhance structural strength, adhesion, and thixotropic properties. However, when such silicone greases are introduced into multiphase systems or non-silicone systems (such as mineral oil, polyether, ester media, and oil-based coating systems containing polar resins or solvents), poor compatibility often occurs due to differences in interfacial polarity, resulting in problems such as layering, oil separation, and uncontrollable thixotropic behavior. To improve its adaptability in complex media, existing technologies often use physical blending to introduce polymer thickeners, surfactants, or silicone-modified resins. However, this physical blending strategy has obvious drawbacks: the added functional polymers are prone to migration or precipitation and are difficult to interact effectively with the three-dimensional network of silicone grease, leading to significant deterioration of the system's rheological properties and interfacial performance after long-term storage or thermal cycling, failing to meet the consistency and reliability requirements of industrial applications.

[0005] Therefore, there is an urgent need to develop a novel composite silicone grease technology that can stably integrate functional polymers into the silicone grease network through molecular-level chemical design and controllable preparation processes. This would enable excellent compatibility, precisely controllable rheological behavior, and performance stability under long-term storage and use conditions in a wide range of oil-based systems, providing an efficient and reliable defoaming and rheological solution for high-performance oil-based coatings (especially architectural protective coatings). Summary of the Invention

[0006] The purpose of this invention is to provide an in-situ polymerized acrylate-organosilicon composite silicone grease and its preparation method, which enables the silicone-containing acrylate copolymer to be stably embedded in the silicone grease network through "in-situ polymerization of silicone grease medium", thereby improving the system compatibility, reducing the risk of oil separation and stratification, and achieving control over its rheological stability; at the same time, the introduction of acrylate-modified organosilicon further improves the interfacial wettability and system stability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An in-situ polymerized acrylate-silicone composite silicone grease, comprising the following components by weight percentage:

[0009] Thixotropic silicone grease matrix G 50-80%, silicone-containing acrylate copolymer P 5-30%, acrylate-modified organosilicon R 2-20%, emulsifier E 0.1-5%.

[0010] Furthermore, the thixotropic silicone grease matrix G is a silicone grease composed of polyorganosiloxane, silica, and MQ resin; the polyorganosiloxane is selected from one or more of polydimethylsiloxane, methylphenyl polyorganosiloxane, and methylhydropolyorganosiloxane with a viscosity of 10-1000 mPa·s at 25°C; the silica is selected from fumed silica and / or precipitated silica with a specific surface area of ​​50-400 m² / g; and the MQ silicone resin is composed of repeating units (CH3)3SiO l / 2 (M unit) and chain link SiO 4 / 2 The MQ resin composed of (Q units) has a molar ratio of (0.4~1.2):1.0.

[0011] Furthermore, the silicone-containing acrylate copolymer P is obtained by free radical copolymerization of acrylate M and vinyl polyorganosiloxane V under the action of initiator system I; furthermore, the acrylate M is a C4-C24 (meth)acrylate alkyl ester, specifically selected from one or more of butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate (2-EHA), isodecanyl acrylate, isobornyl methacrylate (IBOMA), lauryl methacrylate (LMA), and octadecyl methacrylate;

[0012] Furthermore, the vinyl polyorganosiloxane V is at least one polysiloxane with the following structural formula: wherein R 1 Whether the same or different, they are alkyl or vinyl groups with 1 to 10 carbon atoms; R 2 Whether the same or different, they are alkyl or vinyl groups with 1 to 10 carbon atoms; the subscript m is an integer from 0 to 50; n is an integer from 0 to 5; s is an integer from 0 to 30; each molecule has at least one silicon-bonded vinyl group;

[0013]

[0014] Or the general formula is [CH2=CH(Me)SiO] g Cyclic vinyl polyorganosiloxanes, where Me is methyl and g is an integer from 3 to 5;

[0015] The initiator system is a thermal initiator, specifically selected from any one of benzoyl peroxide, lauroyl peroxide, tert-butyl peroxide benzoate, diisopropyl peroxide dicarbonate, diethylhexyl peroxide dicarbonate, potassium persulfate, ammonium persulfate, AIBN, ABVN, and AMBN.

[0016] Furthermore, the emulsifier E is a nonionic surfactant, specifically selected from fatty alcohol polyoxyethylene ether, oleic acid polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty amine compound, polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monopalmitate (Tween-40), polyoxyethylene sorbitan monostearate (Tween-60), polyoxyethylene sorbitan monooleate (Tween-80), polyoxyethylene sorbitan trioleate (Tween-85), sorbitan monolaurate (Span-20), sorbitan monopalmitate (Span-40), sorbitan monostearate (Span-60), sorbitan monooleate (Span-80), and sorbitan trioleate (Span-85), used alone or in combination;

[0017] An in-situ polymerized acrylate-organic silicone composite grease, characterized in that the preparation method of the composite silicone grease is as follows:

[0018] (1) Add polyorganosiloxane and MQ resin into a container and raise the temperature to 80-200℃. Stir and mix evenly, slowly add fumed silica, control the system temperature at 80-150℃, keep warm for 3-5h, and finally react for 1-2h under a vacuum of -0.01--0.08MPa. Finally, cool to room temperature to obtain thixotropic silicone grease matrix G.

[0019] (2) Under nitrogen protection, add acrylate M and vinyl polysiloxane V to the container, raise the temperature to 40-140℃, stir and mix thoroughly, slowly add initiator system I, add for 1-3 hours, keep warm for 2-6 hours after addition, and obtain silicone acrylate copolymer P.

[0020] (3) Add the silicone acrylate copolymer P to the thixotropic silicone grease matrix G, add emulsifier E to disperse it evenly, keep the temperature at 40-120℃, and after the composite is uniform, pass it through a colloid mill to obtain a composite mixture. Add acrylate-modified organosilicon R to the obtained composite mixture, stir and mix evenly, and then pass it through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) This invention uses polyorganosiloxane to construct a thixotropic silicone grease matrix, and combines it with in-situ polymerization to prepare a silicone-containing acrylate copolymer P, which is then stably integrated into the silicone grease network through a compounding method. Compared with the ordinary silicone grease used in the prior art, this composite structure significantly improves the compatibility and storage stability with oil-based coatings and ink systems, and effectively inhibits component migration and precipitation; at the same time, it also shows obvious advantages in defoaming and foam suppression performance, especially in efficiently eliminating micron-sized microbubbles that are difficult to remove from the system, thereby improving the surface quality of the coating film and enhancing the density and protective performance of the coating.

[0023] (2) By introducing acrylate-modified organosilicon R and combining it with homogenization process, the microstructure of the composite silicone grease is made more uniform and dense, which significantly enhances its compatibility in complex non-silicone systems such as mineral oil, polyether, ester and polar resin / solvent, effectively avoiding problems such as layering, oil separation and interface mismatch, thereby broadening its application scope in oil-based coatings, inks and other multiphase industrial systems. Detailed Implementation

[0024] Preparation of thixotropic silicone grease matrix G:

[0025]

[0026] Preparation of silicone-containing acrylate copolymer P:

[0027] Under nitrogen protection, acrylate M (isooctyl acrylate) and vinyl polysiloxane V ((CH2=CH)Me2SiOSiMe2(CH=CH2)) were added to a container. The temperature was raised to 50°C, and after thorough mixing, initiator system I (benzoyl peroxide) was slowly added dropwise over a period of 2 hours. After the addition was completed, the temperature was maintained for 4 hours to obtain silicone acrylate copolymer P1.

[0028] Under nitrogen protection, acrylate M (octadecyl methacrylate) and vinyl polysiloxane V ((Me(CH2=CH)SiO)4) were added to a container. The temperature was raised to 70°C, and after thorough mixing, initiator system I (AIBN) was slowly added dropwise over a period of 2.5 h. After the addition was completed, the temperature was maintained for 5 h to obtain silicone acrylate copolymer P2.

[0029] Under nitrogen protection, acrylate M (isodecyl acrylate) and vinyl polyorganosiloxane V ((Me(CH2=CH)SiO)3) were added to a container. The temperature was raised to 60°C, and after thorough mixing, initiator system I (diethylhexyl peroxide) was slowly added dropwise over a period of 1.5 h. After the addition was completed, the temperature was maintained for 6 h to obtain silicone acrylate copolymer P3.

[0030] Under nitrogen protection, acrylate M (a mixture of isodecyl acrylate and octadecyl methacrylate) and vinyl polyorganosiloxane V ((Me(CH2=CH)SiO)5) were added to a container. The temperature was raised to 120°C, and after thorough mixing, initiator system I (AMBN) was slowly added dropwise over a period of 2 hours. After the addition was completed, the temperature was maintained for 2 hours to obtain silicone acrylate copolymer P4.

[0031] Under nitrogen protection, acrylate M (butyl acrylate) and vinyl polysiloxane V ((CH2=CH)Me2SiO (Me2SiO)) are added to the container. 18 SiMe2(CH=CH2)

[0032] The temperature was raised to 90℃, and after thorough mixing, initiator system I (lauroyl peroxide) was slowly added dropwise over a period of 1.5 h. After the addition was complete, the temperature was maintained for 3.5 h to obtain silicone acrylate copolymer P5.

[0033] Under nitrogen protection, acrylate M (a mixture of isodecyl acrylate and isooctyl acrylate) and vinyl polyorganosiloxane V ((CH2=CH)Me2SiO((CH2=CH)2SiO)2(Me2SiO) are added to the container. 10 SiMe2(CH=CH2)), raise the temperature to 100℃, stir and mix thoroughly, then slowly add initiator system I (ammonium persulfate) over 2 hours. After the addition is complete, keep warm for 4.5 hours to obtain silicone acrylate copolymer P6.

[0034] Under nitrogen protection, acrylate M (a mixture of butyl acrylate and octadecyl methacrylate) and vinyl polysiloxane V (CH3(CH2)) are added to the container. 15 Me2SiO((CH2=CH)2SiO)2(Me2SiO) 20 SiMe2(CH2) 15 CH3), raise the temperature to 140℃, stir and mix thoroughly, and slowly add initiator system I (AMBN) dropwise over 2 hours. After the addition is complete, keep warm for 2 hours to obtain silicone acrylate copolymer P7.

[0035] Under nitrogen protection, acrylate M (a mixture of isodecyl acrylate, butyl acrylate and octadecyl methacrylate) and vinyl polyorganosiloxane V ((CH2=CH)Me2SiO((CH3(CH2))) are added to a container. 10 )2SiO)2(Me2SiO) 25SiMe2(CH2=CH)), raise the temperature to 120℃, stir and mix thoroughly, then slowly add initiator system I (tert-butyl peroxide benzoate) over 2.5 h, and keep warm for 5 h after the addition is complete to obtain silicone acrylate copolymer P8;

[0036] Under nitrogen protection, acrylate M (butyl acrylate) and vinyl polysiloxane V ((CH2=CH)Me2SiO(Me2SiO)) are added to the container. 30 (Me3Si(Me2SiO)3MeSiO)5SiMe2(CH=CH2)), raise the temperature to 90℃, stir and mix thoroughly, then slowly add initiator system I (lauroyl peroxide) dropwise over 1.5 h, and keep warm for 3.5 h after the addition is complete to obtain silicone acrylate copolymer P9;

[0037] Under nitrogen protection, acrylate M (butyl acrylate) and vinyl polysiloxane V ((CH2=CH)Me2SiO(Me2SiO)) are added to the container. 10 (Me3Si((CH3(CH2)8)2SiO)3MeSiO)5SiMe2(CH=CH2)), raise the temperature to 90℃, stir and mix thoroughly, then slowly add initiator system I (lauroyl peroxide) dropwise over 1.5h, and keep warm for 3.5h after the addition is complete to obtain silicone acrylate copolymer P10;

[0038] Under nitrogen protection, acrylate M (a mixture of butyl acrylate and octadecyl methacrylate) and vinyl polysiloxane V (Me3SiO((CH2=CH)2SiO)) are added to the container. 10 (Me2SiO) 30 SiMe3), raise the temperature to 110℃, stir and mix thoroughly, then slowly add initiator system I (AMBN) dropwise over 2 hours. After the addition is complete, keep warm for 2 hours to obtain silicone acrylate copolymer P11.

[0039] Preparation of an in-situ polymerized acrylate-organosilicon composite silicone grease:

[0040] Example 1

[0041] 25 parts of silicone-containing acrylate copolymer P1 were added to 50 parts of thixotropic silicone grease matrix G1, and 5 parts of emulsifier fatty alcohol polyoxyethylene ether were added to disperse it evenly. The temperature was maintained at 100℃. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 20 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0042] Example 2

[0043] 18 parts of silicone-containing acrylate copolymer P2 were added to 61 parts of thixotropic silicone grease matrix G1. 3 parts of a mixture of emulsifier castor oil polyoxyethylene ether and polyoxyethylene sorbitan trioleate were added to disperse the mixture evenly. The temperature was maintained at 120℃. After uniform compounding, the mixture was passed through a colloid mill to obtain a composite mixture. 18 parts of acrylate-modified organosilicon were added to the obtained composite mixture. After stirring and mixing evenly, the mixture was passed through a homogenizer to obtain the in-situ polymerized acrylate-organosilicon composite silicone grease of the present invention.

[0044] Example 3

[0045] Five parts of silicone-containing acrylate copolymer P3 were added to 75 parts of thixotropic silicone grease matrix G2, and 0.5 parts of emulsifier polyoxyethylene dehydrated sorbitan monolaurate were added to disperse it evenly. The temperature was maintained at 75°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 19.5 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0046] Example 4

[0047] 17.9 parts of silicone-containing acrylate copolymer P4 were added to 80 parts of thixotropic silicone grease matrix G2, and 0.1 parts of emulsifier dehydrated sorbitan monooleate were added to disperse it evenly. The temperature was maintained at 65°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 2 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0048] Example 5

[0049] 13.5 parts of silicone-containing acrylate copolymer P5 were added to 78 parts of thixotropic silicone grease matrix G3. 2.5 parts of a mixture of emulsifier dehydrated sorbitan trioleate and polyoxyethylene dehydrated sorbitan trioleate were added to disperse the mixture evenly. The temperature was maintained at 50°C. After uniform compounding, the mixture was passed through a colloid mill to obtain a composite mixture. 6 parts of acrylate-modified organosilicon were added to the obtained composite mixture. After stirring and mixing evenly, the mixture was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0050] Example 6

[0051] 22 parts of silicone-containing acrylate copolymer P6 were added to 65 parts of thixotropic silicone grease matrix G3, and 1 part of emulsifier polyoxyethylene dehydrated sorbitan monopalmitate was added to disperse it evenly. The temperature was maintained at 10°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 12 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0052] Example 7

[0053] 30 parts of silicone-containing acrylate copolymer P7 were added to 53 parts of thixotropic silicone grease matrix G4, and 2 parts of emulsifier dehydrated sorbitan monolaurate were added to disperse it evenly. The temperature was maintained at 50°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 15 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0054] Example 8

[0055] Ten parts of silicone-containing acrylate copolymer P8 were added to 75 parts of thixotropic silicone grease matrix G4. Four parts of a mixture of emulsifier oleic acid polyoxyethylene ether and dehydrated sorbitan monooleate were added to disperse the mixture evenly. The temperature was maintained at 80°C. After the mixture was homogenized, it was passed through a colloid mill to obtain a composite mixture. Eleven parts of acrylate-modified organosilicon were added to the obtained composite mixture. After stirring and mixing evenly, the mixture was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0056] Example 9

[0057] 17.9 parts of silicone-containing acrylate copolymer P9 were added to 80 parts of thixotropic silicone grease matrix G4, and 0.1 parts of emulsifier dehydrated sorbitan monooleate were added to disperse it evenly. The temperature was maintained at 65°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 2 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0058] Example 10

[0059] 13.5 parts of silicone-containing acrylate copolymer P10 were added to 78 parts of thixotropic silicone grease matrix G2. 2.5 parts of a mixture of emulsifiers, polyoxyethylene sorbitan monostearate and polyoxyethylene sorbitan trioleate, were added to disperse the mixture evenly. The temperature was maintained at 50°C. After uniform compounding, the mixture was passed through a colloid mill to obtain a composite mixture. 6 parts of acrylate-modified organosilicon were added to the obtained composite mixture. After stirring and mixing evenly, the mixture was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0060] Example 11

[0061] 22 parts of silicone-containing acrylate copolymer P11 were added to 65 parts of thixotropic silicone grease matrix G3, and 1 part of emulsifier dehydrated sorbitan monostearate was added to disperse it evenly. The temperature was maintained at 10°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 12 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0062] Comparative Example 1

[0063] 25 parts of silicone-containing acrylate copolymer P1 were added to 50 parts of thixotropic silicone grease matrix G1 (wherein the viscosity of the basic small molecule silicone oil in the preparation process of G1 was selected from 10000 mPa·s), and 5 parts of emulsifier fatty alcohol polyoxyethylene ether were added to disperse it evenly. The temperature was maintained at 100℃. After the composite was uniformly compounded, it was passed through a colloid mill to obtain a composite mixture. 20 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0064] Comparative Example 2

[0065] Eighteen parts of silicone-containing acrylate copolymer P2 (wherein the viscosity of the small molecule vinyl silicone oil in the preparation process of P2 is selected from 10000 mPa·s) were added to 61 parts of thixotropic silicone grease matrix G1. Three parts of emulsifier, a mixture of castor oil polyoxyethylene ether and polyoxyethylene sorbitan trioleate, were added to disperse it evenly. The temperature was maintained at 120℃. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. Eighteen parts of acrylate-modified organosilicon were added to the obtained composite mixture. After stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0066] Comparative Example 3

[0067] Five parts of silicone-containing acrylate copolymer P3 (wherein the vinyl polyorganosiloxane V in the preparation process of P3 is only vinyltriethoxysilane) were added to 75 parts of thixotropic silicone grease matrix G2, and 0.5 parts of emulsifier polyoxyethylene dehydrated sorbitan monolaurate were added to disperse it evenly. The temperature was maintained at 75°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 19.5 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0068] Comparative Example 4

[0069] 17.9 parts of common organosilicon polymer were added to 80 parts of thixotropic silicone grease matrix G2, and 0.1 parts of emulsifier sorbitan monooleate were added to disperse it evenly. The temperature was maintained at 65°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 2 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0070] Comparative Example 5

[0071] 13.5 parts of silicone-containing acrylate copolymer P5 were added to 78 parts of thixotropic silicone grease matrix G3, and 2.5 parts of a mixture of emulsifier dehydrated sorbitan trioleate and polyoxyethylene dehydrated sorbitan trioleate were added to disperse it evenly. The temperature was maintained at 50°C. After the composite was uniformly compounded, it was passed through a colloid mill to obtain a composite mixture, which is the in-situ polymerized acrylate-organic silicone composite silicone grease of the present invention.

[0072] Comparative Example 6

[0073] 22 parts of silicone-containing acrylate copolymer P6 were added to 65 parts of thixotropic silicone grease matrix G3, and 1 part of emulsifier polyoxyethylene dehydrated sorbitan monopalmitate was added to disperse it evenly. The temperature was maintained at 10°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 12 parts of acrylate-modified organosilicon were added to the obtained composite mixture and stirred and mixed evenly to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0074] Comparative Example 7

[0075] 30 parts of butyl acrylate were added to 53 parts of thixotropic silicone grease matrix G4, and 2 parts of emulsifier sorbitan monolaurate were added to disperse it evenly. The temperature was maintained at 50°C. After the composite was uniformly mixed, it was passed through a colloid mill to obtain a composite mixture. 15 parts of acrylate-modified organosilicon were added to the obtained composite mixture, and after stirring and mixing evenly, it was passed through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

[0076] Performance testing

[0077] Foam suppression and defoaming performance test:

[0078] High-speed dispersion test method: Add 200ml of the prepared coating to a 1000ml cup, then add 0.3% composite silicone grease. Use a laboratory high-speed disperser to disperse at 1000rpm for 10 minutes. Immediately after stopping, pour the mixture into a 1000ml graduated cylinder, record the weight and volume of the liquid, and calculate the specific gravity. A higher specific gravity indicates a lower air content, suggesting that the composite silicone grease has good defoaming and anti-foaming properties. The test results are as follows:

[0079]

[0080] Characterization of compatibility and microbubble elimination performance:

[0081] Test method: After the above-mentioned high-speed dispersed coating was left to stand for 10 minutes, a small amount was taken out and placed on a glass plate. The coating was then uniformly scraped and leveled using a 75μm wet film preparation device. The state of the coating film was observed and graded as shown in the table below. The lower the crater grade, the better the anti-microbubble effect; the lower the crater size grade, the better the compatibility.

[0082]

[0083] Test results:

[0084]

Claims

1. An in-situ polymerized acrylate-organic silicone composite grease, characterized in that, Components include the following percentages by weight: Thixotropic silicone grease matrix G 50-80%, silicone-containing acrylate copolymer P 5-30%, acrylate-modified silicone R 2-20%, emulsifier E 0.1-5%, the sum of the mass percentages of the above components is 100%; The silicone-containing acrylate copolymer P is obtained by free radical copolymerization of acrylate M and vinyl polyorganosiloxane V under the action of initiator system I; The acrylate M is a C4-C24 (meth)acrylate alkyl ester, specifically selected from one or more of butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate (2-EHA), isodecanyl acrylate, isobornyl methacrylate (IBOMA), lauryl methacrylate (LMA), and octadecyl methacrylate. The vinyl polyorganosiloxane V is at least one polysiloxane with the following structural formula: wherein R 1 Whether the same or different, they are alkyl or vinyl groups with 1 to 10 carbon atoms; R 2 Whether the same or different, they are alkyl or vinyl groups with 1 to 10 carbon atoms; the subscript m is an integer from 0 to 50; n is an integer from 0 to 5; s is an integer from 0 to 30; each molecule has at least one silicon-bonded vinyl group; Or the general formula is [CH2=CH(Me)SiO] g Cyclic vinyl polyorganosiloxanes, where Me is methyl and g is an integer from 3 to 5.

2. The in-situ polymerized acrylate-organic silicone composite grease according to claim 1, characterized in that, The thixotropic silicone grease matrix G is a silicone grease composed of polyorganosiloxane, fumed silica and MQ resin.

3. The in-situ polymerized acrylate-organic silicone composite grease according to claim 2, characterized in that, The polyorganosiloxane is selected from one or more of polydimethylsiloxane, methylphenyl polyorganosiloxane, and methylhydropolyorganosiloxane, which have a viscosity of 10-1000 mPa·s at 25°C.

4. The in-situ polymerized acrylate-organic silicone composite grease according to claim 2, characterized in that, The silica is selected from fumed silica and / or precipitated silica with a specific surface area of ​​50-400 m² / g.

5. The in-situ polymerized acrylate-organic silicone composite grease according to claim 2, characterized in that, The MQ silicone resin is composed of repeating units (CH3)3SiO l / 2 (M unit) and chain link SiO 4 / 2 The MQ resin composed of (Q units) has a molar ratio of (0.4~1.2):1.

0.

6. The in-situ polymerized acrylate-organic silicone composite grease according to claim 1, characterized in that, The initiator system is a thermal initiator, specifically selected from one of benzoyl peroxide, lauroyl peroxide, tert-butyl peroxide benzoate, diisopropyl peroxide dicarbonate, diethylhexyl peroxide dicarbonate, potassium persulfate, ammonium persulfate, AIBN, ABVN, and AMBN.

7. The in-situ polymerized acrylate-organic silicone composite grease according to claim 1, characterized in that, The emulsifier E is a nonionic surfactant, specifically selected from fatty alcohol polyoxyethylene ether, oleic acid polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty amine compounds, polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monopalmitate (Tween-40), polyoxyethylene sorbitan monostearate (Tween-60), polyoxyethylene sorbitan monooleate (Tween-80), polyoxyethylene sorbitan trioleate (Tween-85), sorbitan monolaurate (Span-20), sorbitan monopalmitate (Span-40), sorbitan monostearate (Span-60), sorbitan monooleate (Span-80), and sorbitan trioleate (Span-85), used alone or in combination.

8. A method for preparing an in-situ polymerized acrylate-organosilicon composite silicone grease as described in claims 1-6, characterized in that, Includes the following steps: (1) Add polyorganosiloxane and MQ resin into a container and raise the temperature to 80-200℃. Stir and mix evenly, slowly add fumed silica, control the system temperature at 80-150℃, keep warm for 3-5h, and finally react for 1-2h under a vacuum of -0.01--0.08MPa. Finally, cool to room temperature to obtain thixotropic silicone grease matrix G. (2) Under nitrogen protection, add acrylate M and vinyl polysiloxane V to the container, raise the temperature to 40-140℃, stir and mix thoroughly, slowly add initiator system I, add for 1-3 hours, keep warm for 2-6 hours after addition, and obtain silicone acrylate copolymer P. (3) Add the silicone acrylate copolymer P to the thixotropic silicone grease matrix G, add emulsifier E to disperse it evenly, keep the temperature at 40-120℃, and after the composite is uniform, pass it through a colloid mill to obtain a composite mixture. Add acrylate-modified organosilicon R to the obtained composite mixture, stir and mix evenly, and then pass it through a homogenizer to obtain an in-situ polymerized acrylate-organosilicon composite silicone grease as described in this invention.

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