High-purity branched chain silicone oil as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic silicone oil preparation, in particular to high-purity branched-chain silicone oil as well as a preparation method and application thereof. The method comprises three steps of hydrolytic condensation, secondary hydrolysis and deep condensation which are respectively used for removing residual active groups such as Si-alkoxy and Si-OH in raw materials. By introducing the deep condensation end-capping agent and the catalyst, the intermolecular and intramolecular condensation cross-linking reaction is effectively inhibited, and the purity and stability of the branched chain silicone oil are remarkably improved. The obtained product is controllable in viscosity, small in change in the heat storage period, free of peculiar smell and free of muddy, and is suitable for the fields of personal care, lubrication, electronic materials and the like with high performance requirements. The method is simple in process and suitable for industrial popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of organic silicone oil preparation, and in particular to a high-purity branched silicone oil and a preparation method and application thereof. Background Art

[0002] Branched silicone oils are liquid polyorganosiloxanes containing trifunctional or tetrafunctional segments as branching points within the linear silicone oil molecule. This branched structure creates greater intertwining between the molecules than with linear silicone oils, resulting in a shear-thinning effect that facilitates dispersion and flow. These branches enhance low-temperature resistance (with a freezing point as low as -90°C) while maintaining the many desirable properties of silicone oil. They are widely used in personal care, textiles, low-temperature lubrication, LED silicone rubber, and other applications.

[0003] Conventional methods for preparing branched silicone oils include: (1) alkyl chlorosilane co-hydrolysis method. For example, trimethylchlorosilane, dimethyldichlorosilane, and methyltrichlorosilane are mixed and hydrolyzed to produce MDT branched silicone oil, and MDT silicone oil is then subjected to a ring-opening equilibrium reaction with cyclosiloxane to produce MDT silicone oils of different viscosities. (2) alkyl alkoxysilane co-hydrolysis method. For example, methyltrimethoxysilane and dimethyldimethoxysilane are co-hydrolyzed in the presence of a capping agent such as hexamethyldisiloxane to produce branched silicone oil. (3) 1,1,1,3,5,7,7,7-octamethyl-3,5-dihydroxy-tetrasiloxane (MHTS) is subjected to an equilibrium reaction with cyclosiloxane to prepare branched silicone oil. However, the above methods generally have the defect of incomplete hydrolysis reaction, especially due to the steric hindrance effect, which leads to the inability to fully form the silicon-oxygen bond of the branched structure, and ultimately a large amount of active functional groups such as Si-OH or Si-alkoxy groups remain in the product. Such active functional groups are prone to further hydrolysis or condensation reactions during the storage and use of silicone oils, resulting in increased product viscosity, turbid appearance, odor, and unstable product quality, which seriously limits the application scope of branched silicone oil products.

[0004] A Chinese invention patent (publication number: CN100396715C) involves dropwise adding phenylsilane and a capping agent to water and a catalyst. After hydrolysis, the oil layer is washed with alkali and then with water until neutral. A Chinese invention patent (publication number: CN102329427B) involves dropwise adding a methylchlorosilane mixture to a mixture of methanol and water for hydrolysis. The generated hydrochloric acid is then preferentially removed. Urea is then repeatedly added to promote separation of the acid and water. The mixture is then neutralized with sodium carbonate and filtered, and finally, a secondary equilibrium polymerization is performed in the presence of tetramethylammonium hydroxide to produce MDT silicone oil. A Chinese invention patent (CN103435806B) involves dropwise adding phenyltriethoxysilane to a mixture containing a capping agent, an acidic catalyst, and water. After the addition is complete, the mixture is washed with water until neutral, dried, and then desorbed under reduced pressure to produce branched phenyl silicone oil. The existing technologies all prepare branched silicone oils with T structures by hydrolysis or hydrolysis followed by equilibration. However, due to the presence of steric hindrance during the hydrolysis process, incomplete hydrolysis is very likely to occur, resulting in the presence of active groups such as Si-OH or Si-alkoxy groups. This will cause deep hydrolysis and cross-linking of the product during use or storage, resulting in quality problems such as increased viscosity, wider molecular weight distribution, hazy and turbid appearance, and odor. During storage and use, it brings quality risks such as decreased formula stability, decreased performance, decreased temperature resistance, and easy yellowing, which undoubtedly brings many inconveniences to use.

[0005] To address the risk of residual reactive groups such as Si-OH or Si-alkoxy groups, a Chinese invention patent (publication number: CN108892775B) describes the preparation of a D / T-type cyclic branched siloxane mixture. This involves a balanced catalytic reaction between a trialkoxysilane and a cyclosiloxane, such as D5, in the presence of an acidic macromolecular ion exchange resin. Water and the cyclic D5 are then added to initiate hydrolysis and condensation. Finally, the mixture is neutralized to remove the acid and distilled to remove low-boiling substances such as alcohol and water. This method produces Si-OH and Si-alkoxy groups at a mol% to 10% molar ratio. However, this method focuses on introducing a cyclic structure and still proceeds through a single hydrolysis-condensation reaction. While this method can reduce the number of Si-OH and Si-alkoxy groups to a certain extent, it still cannot fundamentally address the problem of residual reactive groups caused by insufficient hydrolysis. Huang Wenrun proposed in "MT-type siloxane oligomers and polysiloxanes containing MT structures" that, in order to solve the problem of residual active groups such as Si-OH and Si-alkoxy groups, a secondary reaction of the oil layer with concentrated sulfuric acid after the hydrolysis is completed can effectively reduce the Si-OH and Si-alkoxy groups. However, the condensation degree of this method is limited. This method is only effective for the Si-OH part exposed on the outside of the molecular structure, and is almost useless for the Si-OH groups wrapped inside the molecule. In addition, concentrated sulfuric acid has a dehydrating and drying effect, resulting in the Si-alkoxy groups lacking a hydrolysis environment and unable to be removed. Therefore, this method still cannot completely solve the problem of residual active groups such as Si-OH and Si-alkoxy groups.

[0006] In summary, the existing technologies all have the problem of residual active groups such as Si-OH and Si-alkoxy to varying degrees, resulting in low product purity and reduced quality, which in turn limits their application. Summary of the Invention

[0007] To address the existing problems of residual reactive functional groups such as Si-OH and Si-alkoxy groups in branched silicone oils, the present invention aims to provide a method for preparing high-purity branched silicone oils. This method, through the innovative introduction of a secondary hydrolysis process combined with a deep condensation reaction, completely eliminates the problem of residual reactive functional groups such as Si-OH and Si-alkoxy groups caused by insufficient hydrolysis during the production process, thereby obtaining a high-purity and highly stable branched silicone oil product. The implementation of this technical solution will effectively improve the product quality of branched silicone oils, solve the problems of viscosity change, turbid appearance, and performance degradation during storage and use, and significantly expand the application potential of branched silicone oils in fields such as fine chemicals, high-end lubricants, personal care products, and electronic packaging materials.

[0008] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A method for preparing high-purity branched silicone oil comprises the following steps: Step 1: hydrolysis condensation reaction: The capping agent M, the branched chain segment T, and the linear chain segment D are sequentially added to the reactor and mixed evenly. After adding a solvent for dilution, a hydrolysis condensation catalyst and water are added to carry out a first hydrolysis condensation reaction. The acid water layer is removed to obtain a branched silicone oil primary polymer S1. Step 2: Secondary hydrolysis reaction: The branched silicone oil primary polymer S1 obtained in step 1 is diluted with a solvent again, and then a hydrolysis condensation catalyst and water are added to carry out a secondary hydrolysis reaction, the acid water layer is removed, a neutralizing agent is added to neutralize, the solvent is removed, and the product is dried to obtain a neutral and dry branched silicone oil primary polymer S2; Step 3: Deep condensation reaction: Add the branched silicone oil primary polymer S2 obtained in step 2 to the deep condensation capping agent M', and add a deep condensation catalyst to carry out a deep condensation reaction; The capping agent M is a silane compound represented by the general formula R1R2R3-Si-R4, The branched chain segment T is a silane compound represented by the general formula R5Si(R6)3, The linear chain D is a cyclosiloxane or a difunctional silane compound represented by the general formula (R7)2Si(R8)2, The deep condensation sealing agent M' is a silazane compound represented by the general formula (R1R2R3)2Si-NH, wherein R1, R2, R3, R5, and R7 are C1-C 10Alkyl, R4, R8 are C1-C 10 R6 is an alkyl group or a hydrolyzable active group.

[0009] The reaction principle of the present invention is as follows: Hydrolysis condensation reaction: R1R2R3-Si-R4+R5Si(R6)3+(R7)2Si(R8)2 →(R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b1 ((R7)2SiO 2 / 2 ) c1 (R5Si-(OH) x1 (R6) x2 ) d1 ((R7)2SiO(OH) y1 (R8) y2 ) e1 Secondary hydrolysis reaction: (R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b1 ((R7)2SiO 2 / 2 ) c1 (R5Si-(OH) x1 (R6) x2 ) d1 ((R7)2SiO(OH) y1 (R8) y2 ) e1 →(R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b2 ((R7)2SiO 2 / 2 ) c2 (R5Si-(OH) x ) d2 ((R7)2SiO(OH) y ) e2 Deep condensation reaction: (R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b2 ((R7)2SiO 2 / 2 ) c2 (R5Si-(OH) x )d2 ((R7)2SiO(OH) y ) e2 →(R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b ((R7)2SiO 2 / 2 ) c Wherein a=1-100, b=1-2000, c=1-5000, the molecular weight of the branched silicone oil is 1-100000, and the viscosity is 1-10000 mPa.s.

[0010] Preferably, R1, R2, and R3 are the same or different and are one or more of methyl, vinyl, ethyl, propyl, and phenyl; R4 is one or more of methyl, vinyl, ethyl, propyl, and phenyl, or is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy, and butoxy.

[0011] Preferably, R5 is one of methyl, vinyl, ethyl, propyl and phenyl; R6 is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy and butoxy; Preferably, R7 is one or more of methyl, vinyl, ethyl, propyl and phenyl; R8 is one or more of methyl, vinyl, ethyl, propyl and phenyl, or is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy and butoxy.

[0012] Preferably, the sealing agent M is one or more of hexamethyldisiloxane, 1,3-divinyldisiloxane, 1,3-diphenyldisiloxane, 1,3-diethyldisiloxane, trimethylchlorosilane, vinyldimethylchlorosilane, phenyldimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, vinyldimethylmethoxysilane, vinyldiethoxysilane, phenyldimethylmethoxysilane, phenyldimethylethoxysilane, ethyldimethylmethoxysilane and triethylmethoxysilane.

[0013] Preferably, the branched chain segment T is one or more of methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltrichlorosilane.

[0014] Preferably, the linear segment D is one or more of dimethylcyclosiloxane, diethylcyclosiloxane, methylethylcyclosiloxane, methylphenylcyclosiloxane, methylvinylcyclosiloxane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylvinyldichlorosilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, methylphenyldichlorosilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldichlorosilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0015] Preferably, the deep condensation sealing agent M' is one or more of hexamethyldisilazane, 1,3-divinyldisilazane, 1,3-diphenyldisilazane, and 1,3-diethyldisilazane.

[0016] Preferably, the hydrolysis condensation catalyst is one or more combinations of sulfuric acid, hydrochloric acid, sulfonic acid, phosphoric acid, and cation exchange resin.

[0017] The purpose of the solvent is to promote the hydrolysis-condensation reaction by increasing the chance of water contacting the hydrolyzed groups and by diluting the reaction to reduce steric hindrance. Preferably, the solvent is one or more of methanol, ethanol, isopropanol, butanol, benzene, toluene, xylene, dodecyl, hexadecyl, and petroleum ether.

[0018] The neutralizing agent is an alkaline compound used to neutralize the acidic catalyst present in the reaction system until it is neutral. Preferably, the neutralizing agent is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide. The addition form can be alkaline powder or alkaline aqueous solution.

[0019] Deep condensation catalysts include metal catalysts, amine catalysts, metal-free catalysts, and bio-based catalysts. Metal catalysts include organotin catalysts, zinc catalysts, and bismuth catalysts; amine catalysts include primary and secondary amines; metal-free catalysts include guanidines and phosphazene base catalysts; and bio-based catalysts include lipase catalysts. Preferably, the deep condensation catalyst is a metal catalyst, an amine catalyst, a metal-free catalyst, or a bio-based catalyst.

[0020] More preferably, the sealing agent M is one or more of hexamethyldisiloxane, 1,3-divinyldisiloxane, 1,3-diphenyldisiloxane, trimethylchlorosilane, vinyldimethylchlorosilane, trimethylmethoxysilane, vinyldiethoxysilane, and phenyldimethylmethoxysilane.

[0021] More preferably, the branched chain segment T is one or more of methyltrichlorosilane, methyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

[0022] More preferably, the linear segment D is one or more of dimethylcyclosiloxane, methylvinylcyclosiloxane, methylphenylcyclosiloxane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, methylvinyldimethoxysilane, and methylvinyldiethoxysilane.

[0023] More preferably, the hydrolysis condensation catalyst is one or more combinations of sulfuric acid, hydrochloric acid, and sulfonic acid.

[0024] More preferably, the solvent is one or more of ethanol, isopropanol, benzene, and toluene.

[0025] More preferably, the neutralizing agent is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0026] More preferably, the deep condensation catalyst is dibutyltin dilaurate, stannous octoate, triethylenediamine, triethylamine, or hexamethylenetetramine.

[0027] Preferably, the amount of solvent added is 1%-50% of the total amount of the reaction system; more preferably, the amount of solvent added is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% of the total amount of the reaction system.

[0028] And / or, the amount of the hydrolysis condensation catalyst added is 0.1-20% of the total amount of the reaction system; more preferably, the amount of the hydrolysis condensation catalyst added is 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10%, 15% or 20% of the total amount of the reaction system; And / or, the amount of the neutralizer added is 0.1%-20% of the total amount of the reaction system; more preferably, the amount of the neutralizer added is 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10%, 15% or 20% of the total amount of the reaction system; And / or, the addition amount is 1-5000 ppm of the total amount of the reaction system; more preferably, the addition amount is 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000 or 5000 ppm of the total amount of the reaction system.

[0029] Preferably, the amount of solvent added is 20%-40% of the total amount of the reaction system; and / or, the amount of hydrolysis condensation catalyst added is 0.5%-8.0% of the total amount of the reaction system; and / or, the amount of the neutralizer added is 0.5%-8.0% of the total amount of the reaction system; And / or, the added amount is 100-2000ppm of the total amount of the reaction system.

[0030] Preferably, step 1: the capping agent M, the branched chain segment T, and the linear chain segment D are added to a dry reactor in a mass ratio and stirred evenly, and then the solvent is added and stirred for 0.5-2h, and then the mixture of the acidic catalyst and water is slowly added dropwise to the reactor, the reaction system temperature is controlled to be 30-100°C, the addition time is 0.5-5h, and after the addition is completed, the temperature is kept at 30-100°C and the reaction is continued for 1-6h, then the stirring is stopped to separate the layers, and the acid and water layer is removed to obtain the branched silicone oil primary polymer S1.

[0031] Preferably, step 2: add the oil layer branched silicone oil primary polymer S1 to the reactor, add solvent to dilute and stir for 0.5-2h, then slowly dropwise add the mixture of acidic catalyst and water into the reactor, control the temperature of the reaction system to 40-100°C, the dropping time is 0.5-3h, after the dropwise addition is completed, control the temperature to 40-100°C and continue the reaction for 1-6h to carry out secondary hydrolysis reaction, then stop stirring to separate the layers, remove the acid water layer, add a neutralizer to the oil layer for neutralization, remove the residual acid catalyst, and then remove the solvent and dehydrate at 40-80°C under vacuum conditions for 0.5-3h to obtain a neutral, dry branched silicone oil primary polymer S2.

[0032] Preferably, step three: add the neutral, dry branched silicone oil primary polymer S2 to a dry reactor, then add the deep condensation capping agent M', stir evenly for 0.5-2h, then add the deep condensation catalyst, heat while stirring, keep warm at 50-120°C for deep condensation for 1-8h, then remove the water produced by the deep condensation and the low components present in the primary polymer under vacuum conditions at 50-120°C for 0.5-5h, and finally remove color and filter to obtain the high-purity branched silicone oil finished product S3.

[0033] Furthermore, the present invention also provides a high-purity branched silicone oil prepared by the method described above, and the general structural formula of the high-purity branched silicone oil is: (R1R2R3SiO 1 / 2 ) a (R5SiO 3 / 2 ) b ((R7)2SiO 2 / 2 ) c , Wherein a=1-100, b=1-2000, c=1-5000, molecular weight is 1-100000, viscosity is 1-10000mPa.s, total content of Si-OH and Si-alkoxy is less than 0.1mol%, and viscosity growth rate under thermal storage at 80℃ for one month is less than 10%.

[0034] Preferably, a=10-80, b=100-1000, c=100-4000, the molecular weight is 100-80000, and the viscosity is 20-8000 mPa.s.

[0035] More preferably, a=20-60, b=200-8000, c=150-300, the molecular weight is 500-70000, and the viscosity is 50-5000 mPa.s.

[0036] More preferably, a is 30, 40, or 50, b is 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, or 8000, c is 150, 200, 250, or 300, the molecular weight is 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, or 7000, and the viscosity is 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, or 5000 mPa.s.

[0037] Furthermore, the present invention also provides the use of the high-purity branched silicone oil in personal care products, textile treatment agents, low-temperature lubricants and LED packaging silicone rubber.

[0038] The present invention adopts the above-mentioned technical solution to solve the problem of incomplete hydrolysis of branched silicone oil due to steric hindrance during the hydrolysis and condensation process, which is specifically manifested as the problem that residual Si-OH or Si-alkoxy and other active groups are difficult to completely eliminate in a balanced state due to incomplete hydrolysis. In order to solve the problem of residual Si-OH or Si-alkoxy and other active groups, the present invention adopts a method that combines a secondary hydrolysis process with a deep condensation process in order to completely eliminate the residual Si-OH or Si-alkoxy and other active groups. The secondary hydrolysis process is intended to eliminate the Si-alkoxy group, break the equilibrium of the initial hydrolysis, and deeply hydrolyze the Si-alkoxy group under the action of an acidic catalyst to convert it into Si-OH or the desired structure Si-O-Si chain segment. The deep condensation process aims to completely remove the residual Si-OH groups, selectively and specifically condense Si-OH under the catalysis of OH condensation catalyst, and provide capping units by adding deep condensation capping agents, thereby reducing the hydroxyl condensation reaction between and within the polymer molecules, reducing cross-linking and gelation, and converting them into the desired Si-O-Si chain segments, thereby improving the purity of the product and obtaining high-purity branched silicone oil.

[0039] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts an innovative "secondary hydrolysis combined with deep condensation" reaction process, which effectively overcomes the problem of residual active groups such as Si-OH and Si-alkoxy groups caused by incomplete hydrolysis due to steric hindrance in the prior art. The total content of Si-OH and Si-alkoxy groups in the obtained branched silicone oil product is extremely low, which significantly improves the chemical stability and storage stability of the product and avoids the phenomena of increased viscosity, turbid appearance, and odor during storage and use; (2) The present invention improves the end-capping efficiency and selectivity by introducing a specific silazane deep condensation capping agent during the deep condensation process, reduces the condensation cross-linking of hydroxyl groups within and between molecules, further reduces the risk of gel formation, and ensures the good appearance quality and high purity of the branched silicone oil product; (3) Compared with the existing technology, the branched silicone oil product prepared by the present invention has better thermal stability and anti-aging performance. After being placed under the heat storage condition of 80°C for one month, the viscosity growth rate of the product is less than 10%, which is much lower than the comparative product prepared without the method of the present invention (the viscosity growth rate is as high as 40% or more). The product quality stability is significantly improved, and it is more suitable for applications in high-performance and high-reliability applications. (4) The preparation method of the present invention has clear and reasonable steps, mild reaction conditions, simple and easy-to-control process, and the required raw materials are easy to obtain industrially, which greatly improves the feasibility of industrial production of high-purity branched silicone oil and provides good technical guarantee and economic benefits for the market promotion and application development of branched silicone oil products. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0041] Example 1: Step 1: Hydrolysis condensation reaction 40.5 g MM, 396 g phenyltrimethoxysilane (Ph-3M), and 480 g dimethyldimethoxysilane (MM-2M) were added to a dry reactor in sequence and stirred evenly. Then, 30% by mass of ethanol was added and stirred for 0.5 h. Then, a mixture of 2% by mass of concentrated sulfuric acid and 30% by mass of water was slowly added dropwise to the reactor. The temperature of the reaction system was controlled at 60°C and the addition time was 2 h. After the addition was completed, the temperature was kept at 60°C and the reaction was continued for 6 h. Then, stirring was stopped and stratification was carried out. The acid and water layer was removed to obtain the branched silicone oil primary polymer S1.

[0042] Step 2: Secondary hydrolysis reaction The above-mentioned oil layer branched silicone oil primary polymer S1 is added to the reactor, and a solvent is added to dilute and stir for 0.5h. Then, a mixture of the acidic catalyst and water is slowly added dropwise to the reactor, and the temperature of the reaction system is controlled to 60°C. The dropping time is 1h. After the dropwise addition is completed, the temperature is controlled at 60°C and the reaction is continued for 3h to perform a secondary hydrolysis reaction. Then, the stirring is stopped to perform stratification, the acid water layer is removed, and a neutralizer is added to the oil layer for neutralization to remove the residual acid catalyst. Then, the solvent is removed and the dehydration is dried at 60°C under vacuum conditions for 3h to obtain a neutral, dry branched silicone oil primary polymer S2.

[0043] Step 3: Deep condensation reaction The neutral, dry branched silicone oil primary polymer S2 is added to a dry reactor, and then 10% by mass of a deep condensation capping agent (D) hexamethyldisilazane (HMDS) is added and stirred evenly for 1 hour. Then, 1000 ppm of a deep condensation catalyst (E) dibutyltin dilaurate (DBTL) is added and heated while stirring. The mixture is kept at 80°C for deep condensation for 3 hours. Then, the water produced by the deep condensation and the low components in the primary polymer are removed at 80°C under vacuum conditions for 5 hours. Finally, the product is decolorized and filtered to obtain a high-purity branched silicone oil finished product S3 with a viscosity of 285 mPa.s. The viscosity is 293 mPa.s after heat storage at 80°C for 1 month, with a viscosity growth rate of 3%. The appearance is a colorless, transparent, viscous liquid with no change.

[0044] Example 2: Step 1: Hydrolysis condensation reaction 46.5 g of 1,3-divinyldisiloxane (M Vi M Vi ), 630g of methyltriethoxysilane (M-3E) and 1110g of dimethylcyclosiloxane (DMC) were stirred evenly, and then 40% mass parts of toluene were added and stirred for 0.5h. Then, a mixture of 4% mass parts of concentrated hydrochloric acid and 20% mass parts of water was slowly added dropwise into the reactor. The temperature of the reaction system was controlled to 80℃, and the dropping time was 2h. After the dropwise addition was completed, the temperature was kept at 80℃ and the reaction was continued for 6h. After that, the stirring was stopped and the layers were separated. The acid and water layers were removed to obtain the branched silicone oil primary polymer S1.

[0045] Step 2: Secondary hydrolysis reaction The above-mentioned oil layer branched silicone oil primary polymer S1 is added to the reactor, and a solvent is added to dilute and stir for 0.5h. Then, a mixture of the acidic catalyst and water is slowly added dropwise to the reactor, and the temperature of the reaction system is controlled to 80°C. The dropping time is 1h. After the dropwise addition is completed, the temperature is controlled at 80°C and the reaction is continued for 5h for secondary hydrolysis reaction. Then, the stirring is stopped to separate the layers, the acid water layer is removed, and a neutralizer is added to the oil layer for neutralization to remove the residual acid catalyst. Then, the solvent is removed and the dehydration is dried at 80°C under vacuum conditions for 3h to obtain a neutral, dry branched silicone oil primary polymer S2.

[0046] Step 3: Deep condensation reaction The neutral, dry branched silicone oil primary polymer S2 is added to a dry reactor, and then 15% by mass of a deep condensation capping agent (D) 1,3-divinyldisilazane (HViDS) is added, stirred evenly for 1 hour, and then 500ppm of a deep condensation catalyst (E) triethylamine is added, and the mixture is heated while stirring, and kept at 60°C for deep condensation for 5 hours. Then, the water produced by the deep condensation and the low components in the primary polymer are removed at 80°C under vacuum conditions for 5 hours, and finally, the mixture is decolorized and filtered to obtain a high-purity branched silicone oil finished product S3 with a viscosity of 1220mPa.s. The viscosity is 1250mPa.s after heat storage at 80°C for 1 month, with a viscosity growth rate of 2%. The appearance is a colorless, transparent, viscous liquid without change.

[0047] Example 3: Step 1: Hydrolysis condensation reaction 78.5 g of 1,3-diphenyldisiloxane (M Ph M Ph), 930g vinyltrimethoxysilane (Vi-3M) and 1200g dimethyldiethoxysilane (MM-2E) were stirred evenly, and then 50% mass parts of benzene was added and stirred for 0.5h. Then, a mixture of 4% mass parts of sulfonic acid and 32% mass parts of water was slowly added dropwise into the reactor. The temperature of the reaction system was controlled to 80℃, and the dropping time was 2h. After the dropwise addition was completed, the temperature was kept at 80℃ and the reaction was continued for 6h. After that, the stirring was stopped and the layers were separated. The acid and water layers were removed to obtain the branched silicone oil primary polymer S1.

[0048] Step 2: Secondary hydrolysis reaction The above-mentioned oil layer branched silicone oil primary polymer S1 is added to the reactor, and a solvent is added to dilute and stir for 0.5h. Then, the mixture of the acidic catalyst and water is slowly added dropwise to the reactor, and the temperature of the reaction system is controlled to 80°C. The dropping time is 1h. After the dropwise addition is completed, the temperature is controlled at 100°C and the reaction is continued for 5h for secondary hydrolysis reaction. Then, the stirring is stopped to separate the layers, the acid water layer is removed, and a neutralizer is added to the oil layer for neutralization to remove the residual acid catalyst. Then, the solvent is removed and the dehydration is dried at 80°C under vacuum conditions for 3h to obtain a neutral, dry branched silicone oil primary polymer S2.

[0049] Step 3: Deep condensation reaction The neutral, dry branched silicone oil primary polymer S2 is added to a dry reactor, and then 15% by mass of a deep condensation capping agent (D) 1,3-diphenyldisilazane (HPhDS) is added, stirred evenly for 1 hour, and then 300 ppm of a deep condensation catalyst (E) bicyclic guanidine catalyst (TBD) is added. The mixture is heated while stirring and kept at 100°C for deep condensation for 4 hours. The water produced by the deep condensation and the low components in the primary polymer are then removed at 80°C under vacuum conditions for 5 hours. Finally, the mixture is subjected to color removal and filtration to obtain a high-purity branched silicone oil finished product S3 with a viscosity of 3210 mPa.s. The viscosity is 3450 mPa.s after heat storage at 80°C for one month, with a viscosity growth rate of 7%. The appearance of the product is a colorless, transparent, viscous liquid with no change.

[0050] Comparative Example 1-1: Step 1: Hydrolysis condensation reaction To a dry reactor, 40.5g of MM, 396g of phenyltrimethoxysilane (Ph-3M), and 480g of dimethyldimethoxysilane (MM-2M) were added sequentially and stirred until uniform. 30% by weight of ethanol was added and stirred for 0.5h. A mixture of 2% by weight of concentrated sulfuric acid and 30% by weight of water was then slowly added dropwise to the reactor. The reaction system temperature was controlled at 60°C for 2h. After the addition was complete, the reaction was maintained at 60°C and continued for 6h. Stirring was stopped to allow separation and removal of the acidic and aqueous layers. A neutralizer was then added to neutralize the mixture until neutral. Water produced by deep condensation and low-level components in the primary polymer were removed under vacuum at 80°C for 5h. Finally, the product was decolorized and filtered to obtain the finished branched silicone oil. The viscosity was 258mPa.s. After one month of heat storage at 80°C, the viscosity reached 367mPa.s, a 42% viscosity increase. The initial colorless, transparent, viscous liquid became turbid with an odor. Analysis shows that the reason is that the residual Si-OH is deeply condensed between and within the molecules, resulting in an increase in viscosity, and the residual Si-methoxy is removed to form methanol, which is free in the branched silicone oil, causing the appearance to become hazy and turbid and have an odor.

[0051] Comparative Example 1-2: Step 1: Hydrolysis condensation reaction 40.5 g MM, 396 g phenyltrimethoxysilane (Ph-3M), and 480 g dimethyldimethoxysilane (MM-2M) were added to a dry reactor in sequence and stirred evenly. Then, 30% by mass of ethanol was added and stirred for 0.5 h. Then, a mixture of 2% by mass of concentrated sulfuric acid and 30% by mass of water was slowly added dropwise to the reactor. The temperature of the reaction system was controlled at 60°C and the addition time was 2 h. After the addition was completed, the temperature was kept at 60°C and the reaction was continued for 6 h. Then, stirring was stopped and stratification was carried out. The acid and water layer was removed to obtain the branched silicone oil primary polymer S1.

[0052] Step 2: Secondary hydrolysis reaction The branched silicone oil prepolymer S1 from the oil layer was added to a reactor, diluted with solvent and stirred for 0.5 hours. A mixture of an acidic catalyst and water was then slowly added dropwise to the reactor. The reaction system temperature was maintained at 60°C for 1 hour. After the addition was complete, the reaction was maintained at 60°C for 3 hours for secondary hydrolysis. Stirring was then stopped to allow the layers to separate. The acidic and aqueous layers were removed, and a neutralizer was added to the oil layer to neutralize the residual acidic catalyst. The solvent was then removed and the product was dried under vacuum at 60°C for 3 hours to yield a neutral, dry branched silicone oil. The viscosity was 266 mPa.s. After one month of heat storage at 80°C, the viscosity reached 399 mPa.s, representing a 48% viscosity increase. The appearance remained unchanged as a colorless, transparent, viscous liquid. Analysis suggests that the methoxy groups were largely removed through secondary hydrolysis, but the remaining Si-OH groups experienced extensive intermolecular and intramolecular condensation, resulting in significant viscosity growth.

[0053] Comparative Examples 1-3: Step 1: Hydrolysis condensation reaction 40.5 g MM, 396 g phenyltrimethoxysilane (Ph-3M), and 480 g dimethyldimethoxysilane (MM-2M) were added to the dry reactor in sequence and stirred evenly. After that, 30% by mass of ethanol was added and stirred for 0.5 h. Then, a mixture of 2% by mass of concentrated sulfuric acid and 30% by mass of water was slowly added dropwise to the reactor. The temperature of the reaction system was controlled to be 60°C, and the dropping time was 2 h. After the dropwise addition was completed, the temperature was kept at 60°C and the reaction was continued for 6 h. Then, the stirring was stopped and the layers were separated. The acidic water layer was removed, and a neutralizer was added to the oil layer for neutralization to remove the residual acidic catalyst. Then, the solvent was removed and the dehydration was carried out at 60°C under vacuum conditions for 3 h to obtain a branched silicone oil primary polymer.

[0054] Step 2: Deep condensation reaction The neutral, dry branched silicone oil primary polymer is added to a dry reactor, and then 10% by mass of a deep condensation capping agent (D) hexamethyldisilazane (HMDS) is added and stirred evenly for 1 hour. Then, 1000 ppm of a deep condensation catalyst (E) dibutyltin dilaurate (DBTL) is added and heated while stirring. The mixture is kept at 80°C for deep condensation for 3 hours. Then, the water produced by the deep condensation and the low components present in the primary polymer are removed at 80°C under vacuum conditions for 5 hours. Finally, the product is decolorized and filtered to obtain a finished branched silicone oil with a viscosity of 278 mPa.s. The viscosity is 320 mPa.s after heat storage at 80°C for 1 month, with a viscosity growth rate of 15%. The appearance changes from a colorless, transparent, viscous liquid to a hazy, turbid liquid. Analysis shows that the reason is that the residual Si-OH is effectively removed and capped by the condensation capping agent in the presence of a deep condensation catalyst and a deep condensation capping agent, so the viscosity growth change is relatively small; however, the remaining Si-methoxy group removes the methoxy group to form methanol during the thermal storage process, causing secondary condensation to increase the viscosity, and the free methanol cannot dissolve the branched silicone oil, resulting in it being wrapped by the branched silicone oil, causing a hazy and turbid appearance, and accompanied by a solvent odor.

[0055] Comparative Examples 1-4: Step 1: Hydrolysis condensation reaction 40.5 g MM, 396 g phenyltrimethoxysilane (Ph-3M), and 480 g dimethyldimethoxysilane (MM-2M) were added to a dry reactor in sequence and stirred evenly. Then, 30% by mass of ethanol was added and stirred for 0.5 h. Then, a mixture of 2% by mass of concentrated sulfuric acid and 30% by mass of water was slowly added dropwise to the reactor. The temperature of the reaction system was controlled at 60°C and the addition time was 2 h. After the addition was completed, the temperature was kept at 60°C and the reaction was continued for 6 h. Then, stirring was stopped and stratification was carried out. The acid and water layer was removed to obtain the branched silicone oil primary polymer S1.

[0056] Step 2: Secondary hydrolysis reaction The above-mentioned oil layer branched silicone oil primary polymer S1 is added to the reactor, and a solvent is added to dilute and stir for 0.5h. Then, a mixture of the acidic catalyst and water is slowly added dropwise to the reactor, and the temperature of the reaction system is controlled to 60°C. The dropping time is 1h. After the dropwise addition is completed, the temperature is controlled at 60°C and the reaction is continued for 3h to perform a secondary hydrolysis reaction. Then, the stirring is stopped to perform stratification, the acid water layer is removed, and a neutralizer is added to the oil layer for neutralization to remove the residual acid catalyst. Then, the solvent is removed and the dehydration is dried at 60°C under vacuum conditions for 3h to obtain a neutral, dry branched silicone oil primary polymer S2.

[0057] Step 3: Deep condensation reaction The neutral, dry branched silicone oil prepolymer S2 was added to a dry reactor, followed by the addition of 1000 ppm of a deep condensation catalyst (E), dibutyltin dilaurate (DBTL). The product was heated with stirring at 80°C for deep condensation for 3 hours. The water produced by the deep condensation and the low-level components present in the prepolymer were then removed under vacuum at 80°C for 5 hours. Finally, the product was color-removed and filtered to obtain the high-purity branched silicone oil S3. The product had a viscosity of 282 mPa.s. After one month of heat storage at 80°C, the viscosity reached 487 mPa.s, a 73% viscosity increase. The product changed from a colorless, transparent, viscous liquid to a partially gelled viscous liquid. This change was attributed to the fact that, while the branched silicone oil effectively removed residual Si-methoxy groups through secondary hydrolysis, the absence of a silazane-based capping agent during the deep condensation process limited Si-OH condensation to intra- and intermolecular condensation, resulting in an exponential increase in the product's molecular weight. However, due to the cross-linked network structure of the T-linked segments, gel formation was highly likely to occur during the condensation process, leading to poor product fluidity.

[0058]

[0059] The above is a description of the embodiments of the present invention. The above description of the disclosed embodiments will enable professionals in the field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing high-purity branched silicone oil, characterized in that: The steps include: Step 1: hydrolysis condensation reaction: The capping agent M, the branched chain segment T, and the linear chain segment D are sequentially added to the reactor and mixed evenly. After adding a solvent for dilution, a hydrolysis condensation catalyst and water are added to carry out a first hydrolysis condensation reaction. The acid water layer is removed to obtain a branched silicone oil primary polymer S1. Step 2: Secondary hydrolysis reaction: The branched silicone oil primary polymer S1 obtained in step 1 is diluted with a solvent again, and then a hydrolysis condensation catalyst and water are added to carry out a secondary hydrolysis reaction, the acid water layer is removed, a neutralizing agent is added to neutralize, the solvent is removed, and the product is dried to obtain a neutral and dry branched silicone oil primary polymer S2; Step 3: Deep condensation reaction: Add the branched silicone oil primary polymer S2 obtained in step 2 to the deep condensation capping agent M', and add a deep condensation catalyst to carry out a deep condensation reaction; The capping agent M is a silane compound represented by the general formula R1R2R3-Si-R4, The branched chain segment T is a silane compound represented by the general formula R5Si(R6)3, The linear chain D is a cyclosiloxane or a difunctional silane compound represented by the general formula (R7)2Si(R8)2, The deep condensation sealing agent M' is a silazane compound represented by the general formula (R1R2R3)2Si-NH. Wherein R1, R2, R3, R5 and R7 are C1-C 10 Alkyl, R4, R8 are C1-C 10 R6 is an alkyl group or a hydrolyzable active group.

2. The method for preparing a high-purity branched silicone oil according to claim 1, wherein R1, R2, and R3 are one or more of methyl, vinyl, ethyl, propyl, and phenyl; R4 is one or more of methyl, vinyl, ethyl, propyl, and phenyl, or is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy, and butoxy; and / or, R5 is one of methyl, vinyl, ethyl, propyl and phenyl; R6 is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy and butoxy; And / or, R7 is one or more of methyl, vinyl, ethyl, propyl and phenyl; R8 is one or more of methyl, vinyl, ethyl, propyl and phenyl, or is one of trimethylsilyloxy, vinyldimethylsilyloxy, phenyldimethylsilyloxy, ethyldimethylsilyloxy, chlorine, bromine, iodine, methoxy, ethoxy, propoxy and butoxy.

3. The method for preparing a high-purity branched silicone oil according to claim 1, wherein The sealing agent M is one or more of hexamethyldisiloxane, 1,3-divinyldisiloxane, 1,3-diphenyldisiloxane, 1,3-diethyldisiloxane, trimethylchlorosilane, vinyldimethylchlorosilane, phenyldimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, vinyldimethylmethoxysilane, vinyldiethoxysilane, phenyldimethylmethoxysilane, phenyldimethylethoxysilane, ethyldimethylmethoxysilane and triethylmethoxysilane; And / or, the branched chain segment T is one or more of methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltrichlorosilane; and / or the linear segment D is one or more of dimethylcyclosiloxane, diethylcyclosiloxane, methylethylcyclosiloxane, methylphenylcyclosiloxane, methylvinylcyclosiloxane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylvinyldichlorosilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, methylphenyldichlorosilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldichlorosilane, diphenyldimethoxysilane, and diphenyldiethoxysilane; And / or, the deep condensation sealing agent M' is one or more of hexamethyldisilazane, 1,3-divinyldisilazane, 1,3-diphenyldisilazane, and 1,3-diethyldisilazane; and / or, the hydrolysis condensation catalyst is one or more combinations of sulfuric acid, hydrochloric acid, sulfonic acid, phosphoric acid, and cation exchange resin; and / or, the solvent is specifically one or more of methanol, ethanol, isopropanol, butanol, benzene, toluene, xylene, dodecyl, hexadecyl, and petroleum ether; and / or, the neutralizing agent is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide; And / or, the deep condensation catalyst is a metal catalyst, an amine catalyst, a metal-free catalyst or a bio-based catalyst.

4. The method for preparing a high-purity branched silicone oil according to claim 1, wherein The sealing agent M is one or more of hexamethyldisiloxane, 1,3-divinyldisiloxane, 1,3-diphenyldisiloxane, trimethylchlorosilane, vinyldimethylchlorosilane, trimethylmethoxysilane, vinyldiethoxysilane, and phenyldimethylmethoxysilane; And / or, the branched chain segment T is one or more of methyltrichlorosilane, methyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane; and / or the linear segment D is one or more of dimethylcyclosiloxane, methylvinylcyclosiloxane, methylphenylcyclosiloxane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, methylvinyldimethoxysilane, and methylvinyldiethoxysilane; and / or, the hydrolysis condensation catalyst is one or more combinations of sulfuric acid, hydrochloric acid, and sulfonic acid; and / or, the solvent is specifically one or more of ethanol, isopropanol, benzene, and toluene; and / or, the neutralizing agent is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate; And / or, the deep condensation catalyst is dibutyltin dilaurate, stannous octoate, triethylenediamine, triethylamine, or hexamethylenetetramine.

5. The method for preparing a high-purity branched silicone oil according to claim 1, wherein The amount of solvent added is 1%-50% of the total reaction system; and / or, the amount of hydrolysis condensation catalyst added is 0.1%-20% of the total amount of the reaction system; and / or, the amount of the neutralizer added is 0.1%-20% of the total amount of the reaction system; And / or, the added amount is 1-5000 ppm of the total amount of the reaction system.

6. The method for preparing a high-purity branched silicone oil according to claim 1, wherein: The amount of solvent added is 20%-40% of the total reaction system; and / or, the amount of hydrolysis condensation catalyst added is 0.5%-8.0% of the total amount of the reaction system; and / or, the amount of the neutralizer added is 0.5%-8.0% of the total amount of the reaction system; And / or, the added amount is 100-2000ppm of the total amount of the reaction system.

7. The method for preparing a high-purity branched silicone oil according to claim 1, wherein The first hydrolysis condensation reaction in step 1 is as follows: slowly dropwise add the mixture of the acidic catalyst and water into the reactor, control the reaction system temperature to 30-100°C, and add for 0.5-5 hours. After the addition is complete, keep the temperature at 30-100°C and continue the reaction for 1-6 hours; and / or, The secondary hydrolysis reaction in step 2 is as follows: slowly dropwise add the mixture of the acidic catalyst and water into the reactor, control the temperature of the reaction system to 40-100°C, and add for 0.5-3 hours. After the addition is completed, control the temperature to 40-100°C and continue the reaction for 1-6 hours to perform the secondary hydrolysis reaction; and / or, The deep condensation reaction in step three is as follows: after adding the deep condensation catalyst, stir and heat while keeping at 50-120°C for deep condensation for 1-8 hours, and then remove the water produced by the deep condensation and the low components in the initial polymer under vacuum conditions at 50-120°C for 0.5-5 hours.

8. A high-purity branched silicone oil prepared by the method according to any one of claims 1 to 7, wherein the high-purity branched silicone oil has the general structural formula: <h2 style=";text-align:left;direction:ltr">(R1R2R3SiO<h2 style=";text-align:left;direction:ltr"> 1 / 2 <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> a <h2 style=";text-align:left;direction:ltr"> (R5SiO<h2 style=";text-align:left;direction:ltr"> 3 / 2 <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> b <h2 style=";text-align:left;direction:ltr"> (R7)2SiO<h2 style=";text-align:left;direction:ltr"> 2 / 2 <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> c <h2 style=";text-align:left;direction:ltr"> , Wherein a=1-100, b=1-2000, c=1-5000, molecular weight is 1-100000, viscosity is 1-10000mPa.s, total content of Si-OH and Si-alkoxy is less than 0.1mol%, and viscosity growth rate under thermal storage at 80℃ for one month is less than 10%.

9. A high-purity branched silicone oil according to claim 8, characterized in that: a=10-80, b=100-1000, c=100-4000, molecular weight is 100-80000, viscosity is 20-8000mPa.s.

10. Use of the high-purity branched silicone oil according to claim 8 or 9 in personal care products, textile treatment agents, low-temperature lubricants, and LED encapsulation silicone rubber.

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