Sorbitol polyether modified organosilicon surfactant and preparation method thereof

Abstract

The invention relates to the technical field of fine chemical engineering, discloses a sorbitol polyether modified organosilicon surfactant and a preparation method thereof, and solves the problem that the existing polyether modified organosilicon surfactant is poor in weather resistance, function synergy and super-hydrophobic durability. According to the active agent, a fluorine-containing silane group is introduced into a sorbitol polyether chain, a fluorine-silicon-ether ternary synergistic structure is constructed through hydrosilylation, and a molecule comprises a hydrophilic segment, an organic silicon connecting segment and a perfluoroalkyl hydrophobic segment; the preparation method comprises the steps of prepolymer preparation, silicon-hydrogen functionalization and fluorine-containing alkyl introduction through silicon-hydrogen addition. According to the super-hydrophobic and super-oleophobic coating, excellent super-low surface tension and lasting super-hydrophobic and super-oleophobic performance are achieved, the extreme environment tolerance is remarkably improved, and the preparation method is simple, convenient and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical industry and relates to a sorbitol polyether modified organosilicon surfactant and a preparation method thereof. Background Art

[0002] Surfactants, a class of substances capable of significantly altering interfacial properties, play an indispensable role in numerous fields, including industrial production, agricultural plant protection, medicine and health, and daily chemicals. Silicone surfactants, in particular, due to their unique polysiloxane backbone, exhibit surface tension far lower than traditional hydrocarbon surfactants, excellent spreadability, good emulsification and dispersion capabilities, and remarkable resistance to high and low temperatures. These surfactants have garnered widespread attention and ongoing in-depth research in high-value-added applications such as coatings, inks, leather auxiliaries, agrochemicals, personal care products, and textile printing and dyeing.

[0003] For a long time, the development of silicone surfactants has primarily revolved around the structural design of the polysiloxane backbone and the introduction of various types of hydrophilic or lipophilic groups into the side chains to achieve precise control of the hydrophilic-lipophilic balance (HLB value). For example, by grafting polyether chains onto the polysiloxane backbone, the material can be effectively endowed with amphiphilic properties in both aqueous and oil phases, enabling it to function as a highly effective emulsifier, wetting agent, or dispersant. These polyether-modified silicone surfactants, due to their combined organic and inorganic properties, exhibit exceptional performance in reducing surface tension, increasing spreading rate, and improving compatibility with specific systems. Their design principle leverages the low surface energy of the siloxane backbone, combined with the tunable hydrophilicity of the polyether side chains, to enable targeted adsorption at the interface and form a stable adsorption film, effectively reducing interfacial tension and promoting the spreading of liquids or emulsification of two phases. In many common industrial applications, this structure already meets most performance requirements, providing important support for technological advancement in related industries.

[0004] However, with the continued development of related technologies and the increasing demands placed on performance indicators in application scenarios, some inherent characteristics of the aforementioned technical solutions at the principle level have gradually revealed their limitations in responding to new challenges. This is especially true as the application environment becomes increasingly complex and higher standards are placed on the long-term stability, functional synergy, and extreme protection performance of materials. The underlying contradictions are becoming increasingly prominent. The reason for this is that traditional silicone surfactants, even when modified with polyethers to optimize their HLB balance, still have a certain degree of degradation risk in the siloxane backbone of their molecular structure when exposed to harsh environments such as strong ultraviolet radiation, extreme pH values, sustained high temperatures or humidity, and mechanical wear. This leads to a gradual decline in their surface activity and functionality over time, which is known as insufficient weather resistance.

[0005] The deeper problem is that traditional modification methods adopted to improve its environmental stability, such as introducing more rigid groups or increasing the cross-linking density, often sacrifice the flexibility of the molecular segments, diffusion rate and interfacial adsorption efficiency required for it to act as a surfactant. In the pursuit of durability in extreme environments, the intrinsic surface activity of the material may be limited, making it difficult to achieve a perfect synergy between ultra-low surface tension and excellent environmental stability. In addition, relying solely on the combination of siloxane backbone and polyether side chains, it is difficult to effectively introduce and stably maintain advanced protective functions such as superhydrophobicity and superoleophobicity at the molecular level. Even if introduced, there are problems of poor synergy and insufficient durability, resulting in the inability to provide a long-lasting and efficient solution in complex applications that require multiple protective functions (such as antifouling, water resistance, and weather resistance).

[0006] When existing technologies attempt to integrate multiple extreme properties, they can often only do so through simple physical blending or surface coating treatments. This approach can easily lead to component separation, migration, or surface layer peeling, making it difficult to achieve uniform distribution at the molecular level and lasting functional synergy, thus failing to meet the long-term, stable, and multifunctional material requirements of high-performance applications.

[0007] Therefore, how to design a new type of silicone surfactant that not only has excellent surface activity but can also significantly improve its long-term stability in complex and harsh environments through the synergistic effect of its internal molecular structure, and at the same time give it advanced protective functions such as superhydrophobicity, thereby effectively overcoming the deep contradictions of existing technologies in performance synergy, weather resistance and functional durability, has become a key challenge and technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0008] The present invention aims to overcome the technical difficulties faced by existing polyether-modified silicone surfactants in dealing with harsh environments, such as insufficient weather resistance, single functionality, and difficulty in synergistic and stable multifunctionality. It aims to solve the deep technical contradictions that their molecular structure is easily degraded under complex environments such as strong ultraviolet radiation, extreme pH values, continuous high temperature and humidity, and mechanical wear, resulting in attenuation of surface activity and functionality, and it is difficult to effectively introduce and permanently maintain advanced protective functions such as superhydrophobicity at the molecular level. To achieve the above-mentioned purpose of the invention, the present invention provides a sorbitol polyether-modified silicone surfactant and a preparation method thereof, the molecular structure of which comprises at least one sorbitol polyether hydrophilic segment connected by covalent bonding, an organosilicon connecting segment, and a perfluoroalkyl hydrophobic segment, and the molecular structure can be represented by the following general formula:

[0009] R 1 -[O-(C2H4O) x -(C3H6O) y -(C4H8O)2-Si(R 2)2-(CH2) n -Rf] m (I)

[0010] in:

[0011] R 1 It is a sorbitol residue, whose structure is C6H7O(OH)5 or a structure in which some of its hydroxyl groups are substituted. The sorbitol residue serves as a molecular core scaffold, providing multiple reaction sites for connecting polyether chains;

[0012] O-(C2H4O) x -(C3H6O) y -(C4H8O)2 is the polyether segment O-(C2H4O) x -(C3H6O) y -(C4H8O)2, which is connected to the sorbitol residue through an ether bond or an ester bond, wherein (C2H4O) represents an ethylene oxide unit, (C3H6O) represents a propylene oxide unit, and (C4H8O) represents a butylene oxide unit; x, y, and z each independently represent the degree of polymerization of the corresponding alkylene oxide unit, and x, y, and z are non-negative integers, and the average value of their sum (x+y+z) ranges from 10 to 200;

[0013] Si(R 2 ) 2 is an organosilicon unit, which is connected to the end or side chain of the polyether segment through a stable ether bond or silicon-carbon bond, wherein R 2 each independently represents a methyl group, an ethyl group or a phenyl group;

[0014] (CH2) n is an alkylene linking segment, wherein n is an integer from 1 to 10, the alkylene linking segment is connected to the silicon atom of the organosilicon unit through a silicon-carbon bond, and is connected to Rf through a carbon-carbon bond, Rf is a perfluoroalkyl hydrophobic segment;

[0015] Rf is a perfluoroalkyl hydrophobic segment, and its general formula is C p F 2p+1 , wherein p is an integer from 4 to 20;

[0016] m represents the number of polyether-organosilicon-perfluoroalkyl chains connected to the sorbitol residue, and its value is an integer from 1 to 6.

[0017] Preferably, the sorbitol residue is connected to the oxygen atom of the polyether segment through at least one hydroxyl group to form an ether bond;

[0018] When m is an integer less than 6, free hydroxyl groups are still retained on the sorbitol residue, and the retained free hydroxyl groups can further improve the hydrophilicity of the surfactant or provide additional reaction sites.

[0019] Preferably, the total polymerization degree of the ethylene oxide units, propylene oxide units and butylene oxide units in the polyether segment is 20 to 150;

[0020] wherein the proportion of the ethylene oxide unit is 50% to 90%, the proportion of the propylene oxide unit is 10% to 50%, and the proportion of the butylene oxide unit is 0% to 20%;

[0021] The ethylene oxide units, propylene oxide units and butylene oxide units may be distributed in a statistically random, block or gradient manner.

[0022] Preferably, R 2 The organosilicon unit is specifically a dimethylsiloxane group [-Si(CH3)2O-], and the number of repeating units of the organosilicon linking segment is 1 to 5, that is, 1 to 5 organosilicon units can be connected to each polyether chain, and each organosilicon unit is connected to an alkylene linking segment and a perfluoroalkyl hydrophobic segment.

[0023] Preferably, the value of n in the alkylene linking segment is 2 or 3; p in the perfluoroalkyl hydrophobic segment is 6 to 12, and the perfluoroalkyl group is C6F 13 、C8F 17 or C 10 F 21 .

[0024] The present invention discloses a method for preparing a sorbitol polyether modified silicone surfactant, comprising the following steps:

[0025] S1: preparing a sorbitol polyether prepolymer, wherein the prepolymer is a sorbitol core polyether having multiple hydroxyl ends;

[0026] S2: functionalizing the sorbitol polyether prepolymer with a silicon-hydrogen group to form an intermediate product containing a silicon-hydrogen bond;

[0027] S3: introducing a fluorinated alkyl group through a hydrosilylation reaction to synthesize the sorbitol polyether-modified silicone surfactant.

[0028] Preferably, the S1 includes:

[0029] Add sorbitol into a reaction kettle and heat to 90°C to 130°C under stirring; add 0.1% to 0.5% of the mass of sorbitol into a basic catalyst under the protection of inert gas;

[0030] Slowly adding dropwise or passing ethylene oxide, propylene oxide or butylene oxide, wherein the ratio of the total molar amount of the alkylene oxide to the molar amount of sorbitol is 10:1 to 200:1; during the reaction process, the reaction temperature is maintained at 100° C. to 160° C., and the reaction pressure is controlled at 0.2 MPa to 0.8 MPa;

[0031] The reaction is continued until the alkylene oxide monomer in the system is exhausted and the pressure is stable, and then the system is kept warm and aged for 1 to 3 hours. After the reaction is completed, the reaction product is neutralized and the pH of the system is adjusted to 6.0 to 7.0 using an acidic substance.

[0032] After the catalyst salt is removed by filtration, the prepolymer is subjected to a dehydration and degassing treatment at 80° C. to 100° C. and a vacuum degree of -0.08 MPa to -0.095 MPa until the water content of the prepolymer is less than 0.1%.

[0033] Preferably, the S2 includes:

[0034] The sorbitol polyether prepolymer is placed in a reaction kettle and heated to 40° C. to 80° C. under an inert gas atmosphere; and a silicon-hydrogen bond chlorosilane is added at a molar ratio of 1:1 to 1.5:1 based on the hydroxyl content of each mole of the sorbitol polyether prepolymer;

[0035] At the same time, an organic amine is added as an acid acceptor at a molar ratio of 1:1 to 1.2:1; the reactants are dissolved in an aprotic solvent;

[0036] Under stirring conditions, slowly dropwise adding the mixed solution of the silicon-hydrogen bond chlorosilane and the organic amine, and maintaining the reaction temperature at 50° C. to 90° C. during the dropwise addition process;

[0037] After the dropwise addition is completed, the reaction mixture is heated to 80° C. to 120° C. and kept warm for 2 to 6 hours until no hydrogen chloride gas escapes from the system;

[0038] After the reaction is complete, the generated hydrochloride is removed by filtration, and the solvent is removed by rotary evaporation or vacuum distillation.

[0039] Preferably, the S3 includes:

[0040] Adding the intermediate product containing a silicon-hydrogen bond and a perfluoroalkyl monomer containing an unsaturated bond in a molar ratio of 1:0.8 to 1:1.2 into a reaction kettle; dissolving the reactants in an aprotic solvent;

[0041] Under inert gas protection and stirring conditions, the reaction mixture is heated to 60° C. to 100° C.; a platinum catalyst is added in an amount of 0.005% to 0.05% by weight of the unsaturated bond-containing perfluoroalkyl monomer;

[0042] Maintaining the reaction at the temperature for 2 to 8 hours until the characteristic peak of the silicon-hydrogen bond in the system disappears in the Fourier transform infrared spectrum;

[0043] After the reaction is completed, the catalyst and a small amount of unreacted monomers are removed by activated carbon adsorption or silica gel column chromatography, and then the solvent is removed by rotary evaporation or vacuum drying.

[0044] Preferred:

[0045] The alkaline catalyst in S1 is potassium hydroxide or sodium methoxide, and the acidic substance is phosphoric acid or acetic acid;

[0046] The silicon-hydrogen bond chlorosilane in S2 is dimethylchlorosilane or methylhydrogendichlorosilane, the organic amine is triethylamine or pyridine, and the aprotic solvent is toluene, xylene or tetrahydrofuran;

[0047] The unsaturated bond-containing perfluoroalkyl monomer in S3 is 1H,1H,2H,2H-perfluorodecyl acrylate, perfluorohexyl vinyl ether or 1H,1H,2H,2H-perfluorooctyl vinyl ether, the platinum catalyst is a Castaplatin catalyst, and the aprotic solvent is toluene or ethyl acetate.

[0048] The sorbitol polyether modified silicone surfactant disclosed in the present invention has the following significant advantages and positive effects:

[0049] 1. The unique "fluorine-silicon-ether" ternary synergistic structure endows the surfactant of this invention with exceptional ultra-low surface tension properties. The hydrophilic segment of the sorbitol polyether ensures good dispersibility and rapid diffusion of the molecule in aqueous phases or polar solvents. The introduction of the organosilicon linker further reduces the overall surface energy of the molecule. The perfluoroalkyl hydrophobic segment, with its extremely low critical surface tension, enables the product of this invention to rapidly and directionally adsorb at gas-liquid or solid-liquid interfaces and form dense monolayer or multilayer structures. This structure can reduce the surface tension in aqueous solutions to below 15 mN / m, even up to approximately 10 mN / m, significantly improving the spreadability, wettability, and permeability of liquids.

[0050] 2. The present invention achieves excellent and lasting superhydrophobic and superoleophobic properties by covalently linking a perfluoroalkyl segment with high chemical inertness and low surface energy to a sorbitol polyether skeleton through a stable silicon-carbon bond. The self-organized arrangement of the perfluoroalkyl chain at the interface can form a microscopic rough surface with a high contact angle, so that water droplets appear spherical on the surface of the material, and its water contact angle can reach more than 150°, and the sliding angle is less than 10°; at the same time, it also shows significant repulsion to oily liquids, and its oil contact angle can reach more than 80°. Since the hydrophobic / oleophobic group is part of the covalently bonded structure inside the molecule, rather than a simple physical blend or surface adsorption, its performance can still be stably maintained after long-term use, mechanical wear or solvent washing, significantly improving functional durability and overcoming the limitations of the prior art that functional components are easy to migrate and peel off.

[0051] 3. The "fluorine-silicon-ether" synergistic structure designed in the present invention significantly improves the long-term stability of surfactants in extreme environments, that is, weather resistance.

[0052] 4. This invention utilizes sorbitol as a polyhydroxyl core scaffold, combined with the precise design of multi-arm polyether chains, to provide multiple, evenly distributed reaction sites for subsequent silane functionalization. This allows for high-density, highly uniform grafting of fluorinated silane groups into the molecular structure. This multi-point attachment not only improves modification efficiency but also further enhances the overall structural stability of the molecule, effectively avoiding the potential loss of active components and uneven functionality associated with traditional single-point grafting.

[0053] 5. The preparation method provided by the present invention has a clear process route, is easy to operate, has a high yield, and is environmentally friendly. The three-step reaction can be carried out under mild conditions, and the catalysts and solvents used can be recycled by conventional methods, in line with the principles of green chemistry. By precisely controlling the conditions and feed ratios of each reaction step, the molecular weight, hydrophilic-lipophilic balance, fluorine content, and degree of branching of the target product can be flexibly controlled, thereby enabling customized design according to different application requirements to meet diverse market demands.

[0054] 6. The sorbitol polyether-modified silicone surfactant synthesized in this invention can be widely used in high-performance coatings, inks, leather auxiliaries, agricultural chemicals, personal care products, and textile printing and dyeing. In the coating field, it can be used as a high-efficiency wetting agent, leveling agent, and antifouling agent, giving the coating film a super-hydrophobic and self-cleaning function; in agricultural chemicals, it can significantly improve the spreading, penetration, and adhesion of pesticides while enhancing their resistance to rain erosion; in the field of textile printing and dyeing, it can be used as a durable waterproof, oil-proof, and antifouling finishing agent, giving fabrics long-lasting three-proof functions. Its high performance and long-lasting effect in complex and demanding application scenarios can effectively replace existing products with insufficient performance and promote technological upgrading in related industries. DETAILED DESCRIPTION

[0055] This invention provides a sorbitol polyether-modified organosilicon surfactant and its preparation method. This technical solution aims to provide a covalently bonded surfactant with a ternary synergistic "fluorine-silicon-ether" structure at the molecular level, which is expected to exhibit exceptional ultra-low surface tension, long-lasting super-hydrophobic and oleophobic properties, and significantly improved weather resistance in harsh environments.

[0056] The molecular structure of the sorbitol polyether-modified silicone surfactant disclosed herein comprises at least one covalently bonded sorbitol polyether hydrophilic segment, a silicone linker segment, and a perfluoroalkyl hydrophobic segment. The molecular structure can be represented by the following general formula (I):

[0057] R1 -[O-(C2H4O) x -(C3H6O) y -(C4H8O) z -Si(R 2 )2-(CH2) n -Rf] m (I)

[0058] Among them, R 1 Represents a sorbitol residue, which serves as a molecular core scaffold and provides multiple reaction sites for connecting polyether chains. The structure of the sorbitol residue is C6H7O(OH)5. Five of the six hydroxyl groups in the sorbitol molecule are directly connected to the carbon atom, and one is connected to the carbon atom through an ether bond, forming a stable skeleton structure, and these six hydroxyl groups can all serve as potential reaction sites. In practical applications, at least one hydroxyl group of the sorbitol residue forms an ether bond with the oxygen atom of the polyether segment. When the m value is an integer less than 6, it means that some of the hydroxyl groups on the sorbitol residue are not etherified or esterified, and free hydroxyl groups are still retained. These retained free hydroxyl groups can not only further improve the hydrophilicity of the surfactant, but also provide additional reaction sites in specific application scenarios, such as for subsequent cross-linking or anchoring, thereby giving the material more complex functions.

[0059] O-(C2H4O) x -(C3H6O) y -(C4H8O) z represents a polyether segment, which is connected to the sorbitol residue via an ether bond or an ester bond. This segment is composed of ethylene oxide units (C2H4O, propylene oxide units (C3H6O) and butylene oxide units (C4H8O).

[0060] x, y, and z each independently represent the degree of polymerization of the corresponding alkylene oxide unit and are all non-negative integers. The ethylene oxide unit primarily contributes to the hydrophilicity of the molecule in aqueous phase and significantly adjusts its hydrophilic-lipophilic balance; the propylene oxide unit provides a balance between hydrophilicity and hydrophobicity while increasing the flexibility of the molecular chain; and the introduction of the butylene oxide unit generally aims to increase the hydrophobicity of the molecular chain, thereby affecting its solubility and dispersibility in non-polar media.

[0061] The average value of the sum of x, y, and z (x+y+z) ranges from 10 to 200 to ensure that the polyether segments provide suitable hydrophilicity and molecular flexibility. When the total degree of polymerization is less than 10, the molecule may have insufficient hydrophilicity, making it difficult to effectively disperse in the aqueous phase. When the total degree of polymerization exceeds 200, the difficulty and cost of synthesizing the molecule will increase significantly, and the viscosity may be too high, which is not conducive to subsequent processing and application. The ethylene oxide units, propylene oxide units, and butylene oxide units can be distributed in a statistically random, block, or gradient manner. The choice of this distribution method plays a decisive role in regulating the macroscopic properties of the molecule, such as solubility, emulsification ability, and surface adsorption kinetics.

[0062] As a preferred embodiment of the present invention, the total degree of polymerization (x+y+z) of the ethylene oxide units, propylene oxide units, and butylene oxide units in the polyether segment is preferably 20 to 150. The ratio of the ethylene oxide units (x / (x+y+z)) is preferably 50% to 90%. This high ratio ensures that the surfactant has good water solubility or water dispersibility and can effectively adjust its HLB value to the range of 8-15, thereby exhibiting excellent spreading and wetting properties in aqueous systems.

[0063] The ratio of propylene oxide units (y / (x+y+z)) is preferably 10% to 50%, which serves to lower the glass transition temperature of the molecular chain, increase flexibility, and adjust the HLB value, making it suitable for a wider range of applications. The ratio of butylene oxide units (z / (x+y+z)) is preferably 0% to 20%, and is mainly introduced when higher hydrophobicity is required or to provide better solubility in non-polar systems.

[0064] Si(R 2 )2 represents an organosilicon unit, which is connected to the end or side chain of the polyether segment through a stable ether bond or silicon-carbon bond. 2 Each independently represents a methyl group, an ethyl group, or a phenyl group, preferably a methyl group, forming a dimethylsiloxane group [-Si(CH3)2O-]. The organosilicon linker segment preferably has 1 to 5 repeating units. One to five organosilicon units may be attached to each polyether chain, and each organosilicon unit is attached to an alkylene linker segment and a perfluoroalkyl hydrophobic segment.

[0065] The organosilicon linker plays multiple key roles in the molecular structure: first, it provides molecular flexibility, enabling the entire macromolecule to effectively adjust its conformation at the interface to reduce surface energy; second, it serves as a stable bridge connecting the perfluoroalkyl and polyether segments, ensuring that the two functional segments with very different properties can be stably combined through covalent bonding; more importantly, the siloxane chain itself has a low surface energy, and its introduction can further reduce the surface tension of the entire molecule.

[0066] (CH2) n Represents an alkylene linking segment, wherein n is an integer from 1 to 10. The alkylene linking segment is connected to the silicon atom of the organosilicon unit through a silicon-carbon bond, and is connected to the perfluoroalkyl hydrophobic segment through a carbon-carbon bond. The introduction of this linking segment is intended to provide appropriate flexibility to promote the effective arrangement of the perfluoroalkyl segment at the interface, while ensuring that the silicon hydroaddition reaction can proceed efficiently and form a stable covalent bond. Preferably, the preferred value of n is 2, that is, -CH2CH2-, or the preferred value of n is 3, that is, -CH2CH2CH2-. When n is 2, it is usually formed by the addition of vinyl perfluoroalkane and silicon hydrogen bond, which can provide higher reactivity and shorter connection distance. When n is 3, it is usually formed by the addition of allyl perfluoroalkane and silicon hydrogen bond, which can provide a slightly longer flexible chain, which is sometimes beneficial to the reduction of steric hindrance and interface arrangement.

[0067] Rf represents a perfluoroalkyl group, the general formula of which is C p F 2p+1 , wherein p is an integer from 4 to 20. The perfluoroalkyl group has high electronegativity, extremely low surface energy and excellent chemical inertness, thereby giving the surfactant excellent superhydrophobic and superoleophobic properties. Preferably, p is from 6 to 12, ensuring sufficient chain length to form an effective low surface energy interface while taking into account the convenience and cost-effectiveness of synthesis. Specific preferred perfluoroalkyl groups include C6F 13 (perfluorohexyl), C8F 17 (perfluorooctyl) or C 10 F 21 (Perfluorodecyl). These perfluoroalkyl chains, due to their extremely high fluorine content and unique helical structure, can self-organize on the surface of materials to form a tightly packed, low-surface-energy layer, effectively repelling water and oily liquids.

[0068] m represents the number of polyether-organosilicon-perfluoroalkyl chains attached to the sorbitol residue, and is an integer ranging from 1 to 6, with a preferred value of 2 to 4. The choice of m directly determines the degree of branching and functional density of the molecular structure. A higher m value increases the number of functional segments carried by the molecule, resulting in a higher adsorption density at the interface, potentially achieving superior surface properties. Furthermore, the multi-point connection structure enhances the overall structural stability of the molecule, effectively preventing the functional components from falling off in harsh environments.

[0069] The present invention also provides a method for preparing the sorbitol polyether modified silicone surfactant. The method ensures the structural accuracy and performance controllability of the target product through three carefully designed steps.

[0070] S1: Preparation of sorbitol polyether prepolymer (SP-OH):

[0071] This step is intended to synthesize a sorbitol core polyether with multiple hydroxyl ends as the starting material for subsequent functionalization. First, high-purity sorbitol is placed in a closed reactor equipped with an agitator, a thermometer, an inert gas inlet and a pressure control system. Under stirring conditions, the materials in the reactor are heated to 90°C to 130°C. This preheating process is intended to reduce the viscosity of sorbitol, improve its fluidity, and create conditions for the uniform dispersion of the catalyst. Subsequently, under the protection of continuous inert gas (such as high-purity nitrogen), an alkaline catalyst accounting for 0.1% to 0.5% of the mass of sorbitol is added. The alkaline catalyst is preferably potassium hydroxide or sodium methoxide, which can effectively initiate the ring-opening polymerization reaction of alkylene oxide. The presence of inert gas is intended to exclude oxygen, prevent sorbitol from oxidation at high temperatures, and ensure the purity of the polymerization reaction.

[0072] After the catalyst is added and evenly dispersed, ethylene oxide, propylene oxide, or butylene oxide (or any mixture thereof) is slowly added dropwise or introduced at a strictly controlled rate. The ratio of the total molar amount of alkylene oxide to the molar amount of sorbitol is 10:1 to 200:1; this ratio determines the average length of the final polyether chain. Throughout the alkylene oxide addition process, the reaction temperature is strictly maintained between 100°C and 160°C to balance the reaction rate and the suppression of side reactions. Excessively low temperatures will result in an excessively slow reaction rate, while excessively high temperatures may cause excessive etherification or product degradation. Simultaneously, the reaction pressure is controlled between 0.2 MPa and 0.8 MPa by precisely controlling the alkylene oxide addition rate and the pressure regulating valve within the reactor. This pressure range helps maintain the alkylene oxide monomer in the liquid phase or high-pressure gas phase, improving its solubility in the reaction system and promoting uniform reaction.

[0073] The reaction continues until the alkylene oxide monomer in the system is depleted. The consumption is determined by monitoring the pressure change. When the pressure stabilizes and no longer decreases, the polymerization reaction is nearing completion. The reaction mixture is then aged at the specified temperature and pressure for 1 to 3 hours. This aging process ensures that all alkylene oxides are fully reacted and achieves a more uniform molecular weight distribution of the polyether segments. After the reaction, the reaction product is neutralized to remove any residual alkaline catalyst and prevent it from adversely affecting subsequent reactions or product stability. The pH of the system is precisely adjusted to 6.0 to 7.0 using an acidic agent such as phosphoric acid or acetic acid. This pH range converts the alkaline catalyst into easily removable salts. The resulting catalyst salts are completely removed by filtration. Finally, the reaction mixture is dehydrated and degassed at a temperature of 80°C to 100°C and a vacuum of -0.08 MPa to -0.095 MPa. This step utilizes the synergistic effects of high temperature and high vacuum to efficiently remove any residual moisture, unreacted low-molecular-weight substances, and trace gases in the system, reducing the prepolymer's water content to less than 0.1%, ensuring the high purity of the SP-OH prepolymer. The number-average molecular weight of the resulting SP-OH prepolymer is determined by gel permeation chromatography (GPC), and its hydroxyl number is accurately determined by chemical titration. These parameters provide a key basis for calculating feedstock for subsequent reactions.

[0074] S2: Functionalization of sorbitol polyether prepolymer with silicon hydride groups (SP-SiH):

[0075] In this step, a silicon-hydrogen bond is introduced into the molecular chain of a sorbitol polyether prepolymer (SP-OH) by reacting with chlorosilane, thereby forming an intermediate product containing a silicon-hydrogen bond (SP-SiH), which provides an active site for subsequent perfluoroalkyl grafting. The SP-OH prepolymer prepared in S1 is transferred to a reactor. Under an inert gas atmosphere (such as nitrogen), the reactor is heated to 40°C to 80°C. This temperature is intended to reduce the viscosity of SP-OH and facilitate dissolution and mixing. According to the hydroxyl content per mole of SP-OH, a silicon-hydrogen bond chlorosilane is added at a molar ratio of 1:1 to 1.5:1. The silicon-hydrogen bond chlorosilane is preferably dimethylchlorosilane or methylhydrogendichlorosilane. The excess use of chlorosilane (up to 1.5:1) is intended to ensure the complete conversion of hydroxyl groups and improve the reaction yield. At the same time, an organic amine is added at a molar ratio of 1:1 to 1.2:1 as an acid acceptor, and the organic amine is preferably triethylamine or pyridine. The role of organic amines is to neutralize the hydrogen chloride gas produced during the reaction, prevent it from corroding the product or equipment, and promote the reaction toward the product.

[0076] The SP-OH prepolymer, silicon-hydrogen bonded chlorosilane and organic amine are dissolved in an aprotic solvent respectively, and the solvent is preferably toluene, xylene or tetrahydrofuran. The selection of aprotic solvent is intended to avoid side reactions with chlorosilane. Under stirring conditions, the mixed solution of the silicon-hydrogen bonded chlorosilane and organic amine is slowly added dropwise. The dropwise addition process should be controlled over a long period of time to maintain the reaction temperature between 50°C and 90°C, avoid local overheating, and ensure the smooth progress of the reaction. After the dropwise addition is completed, the reaction mixture is heated to 80°C to 120°C and kept at this temperature for 2 to 6 hours. This insulation process is intended to ensure that the reaction of hydroxyl groups with chlorosilanes is complete. By monitoring the changes in the amount of hydrogen chloride gas escaped in the system, when no hydrogen chloride gas escapes, it indicates that the reaction has been basically completed.

[0077] After the reaction is completed, the hydrochloride (such as triethylammonium chloride) produced during the reaction is removed by filtration. Subsequently, the solvent is removed by rotary evaporation or vacuum distillation to obtain a sorbitol polyether intermediate product (SP-SiH) containing silicon-hydrogen bonds. The silicon-hydrogen bond content of the intermediate product is accurately determined by volumetric method or nuclear magnetic resonance spectroscopy, which is crucial for controlling the feed ratio of S3.

[0078] S3: Introduction of fluorinated alkyl groups (SP-Si-F) by hydrosilylation reaction:

[0079] This final step aims to covalently bond an unsaturated perfluoroalkyl monomer to the Si-H bonds of the SP-SiH intermediate via a hydrosilylation reaction, thereby synthesizing the target product—a sorbitol polyether-modified silicone surfactant. The SP-SiH intermediate prepared in S2 and a molar ratio of 1:0.8 to 1:1.2 of an unsaturated perfluoroalkyl monomer are added to a reactor. The unsaturated perfluoroalkyl monomer is preferably 1H,1H,2H,2H-perfluorodecyl acrylate, perfluorohexyl vinyl ether, or 1H,1H,2H,2H-perfluorooctyl vinyl ether. These monomers contain unsaturated bonds, such as olefinic or alkynyl groups, that react efficiently with Si-H bonds. A slight excess or deficiency of the perfluoroalkyl monomer depends on the actual activity of the Si-H bonds and the specific performance requirements of the target product.

[0080] The reactants are dissolved in an aprotic solvent, preferably toluene or ethyl acetate, which have good solubility and a suitable boiling point. Under inert gas protection and stirring conditions, the reaction mixture is heated to 60° C. to 100° C. Subsequently, a platinum catalyst accounting for 0.005% to 0.05% by mass of the perfluoroalkyl monomer is added. The platinum catalyst is preferably a Castell platinum catalyst, which has excellent catalytic activity and selectivity and can efficiently catalyze the hydrosilylation reaction. The reaction is maintained at the temperature for 2 to 8 hours. The reaction progress is monitored in real time by Fourier transform infrared spectroscopy of the characteristic peaks of the silicon-hydrogen bond. When the characteristic peaks of the silicon-hydrogen bond completely disappear in FTIR, it indicates that the hydrosilylation reaction has been completed.

[0081] After the reaction is completed, the residual platinum catalyst and a small amount of unreacted monomer are removed by methods such as activated carbon adsorption or silica gel column chromatography to ensure the purity of the final product. Activated carbon can adsorb organic impurities and catalyst residues, while silica gel column chromatography can achieve more refined separation. Finally, the solvent is removed by rotary evaporation or vacuum drying to obtain the sorbitol polyether-modified silicone surfactant product described in the present invention. The surface tension of the final product is measured by the platinum plate method or the hanging drop method, the water contact angle and oil contact angle are measured by an optical contact angle meter, the elemental composition is determined by an elemental analyzer, and the molecular structure is confirmed by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. These detailed characterization methods ensure a comprehensive understanding and verification of the structure and properties of the synthesized product.

[0082] The following will further illustrate the specific implementation of the sorbitol polyether modified silicone surfactant and the preparation method thereof of the present invention through specific examples and comparative examples, and provide quantitative data to prove its technical effect.

[0083] Example 1: Preparation and properties of sorbitol polyether-dimethylsiloxane-perfluorooctyl copolymer.

[0084] Preparation of sorbitol polyether prepolymer (SP-OH):

[0085] 200g (1.1 mol) of high-purity sorbitol was added to a 2L reactor equipped with a mechanical stirrer, a thermometer, an inert gas inlet, and a pressure sensor. Under nitrogen protection, the sorbitol was heated to 110°C. 0.5g (0.25% by weight of the sorbitol) of powdered potassium hydroxide was added as a catalyst and stirred to dissolve it. Subsequently, a total of 1100g of ethylene oxide (approximately 25 mol) and 300g of propylene oxide (approximately 5.17 mol) were slowly introduced at 120°C to 150°C and a pressure of 0.5MPa, i.e., the ratio of the total molar amount of ethylene oxide to the molar amount of sorbitol was approximately 27.4:1. Ethylene oxide and propylene oxide were introduced in a statistically random manner. The reaction continued for about 6 hours until the pressure in the reactor stabilized. After the reaction was completed, the reaction was kept warm and aged for 2 hours. Then, the reaction was cooled to 80°C and 1.5g of phosphoric acid (85% aqueous solution) was added to adjust the pH value of the system to 6.5. The potassium phosphate was removed by filtration. The mixture was then dehydrated and degassed at 90°C and -0.09 MPa vacuum for 4 hours to obtain a transparent, viscous sorbitol polyether prepolymer (SP-OH). GPC analysis revealed a number-average molecular weight (Mn) of 1950 g / mol and a hydroxyl number of 300 mg KOH / g. This prepolymer contained approximately 6 hydroxyl groups.

[0086] Silicon hydride functionalization (SP-SiH):

[0087] 500g of the SP-OH prepolymer prepared above (about 0.25 mole, containing about 1.5 moles of hydroxyl groups) was transferred to a 2L reactor. Under a nitrogen atmosphere, it was heated to 60°C. 250g (1.94 moles) of dimethylchlorosilane and 200g (1.98 moles) of triethylamine were dissolved in 500mL of dry toluene, and the two solutions were then mixed. Under vigorous stirring, this mixed solution was slowly added dropwise to the SP-OH prepolymer, and the dropwise addition rate was controlled to complete within 2 hours to ensure that the reaction temperature was maintained at 70°C to 80°C. After the addition was complete, the reaction mixture was heated to 100°C and kept incubated for 4 hours until no hydrogen chloride gas was detected. After cooling to room temperature, the white solid triethylamine hydrochloride was removed by pressure filtration. The filtrate was removed by rotary evaporation at 60°C and a vacuum of -0.08MPa to remove the toluene solvent to obtain a light yellow, transparent sorbitol polyether intermediate (SP-SiH) containing a silicon-hydrogen bond. 1 H-NMR analysis showed that the conversion rate of Si-H bonds reached over 95%, and the Si-H bond content was 0.8 mol / 100 g.

[0088] Introduction of fluorinated alkyl (SP-Si-F) and synthesis of target product:

[0089] 400 g of the SP-SiH intermediate product prepared above (about 0.8 moles of silicon-hydrogen bonds) and 280 g (0.6 moles) of 1H,1H,2H,2H-perfluorooctyl vinyl ether were added to a 1 L reactor. 600 mL of dry toluene was added as a solvent. Under nitrogen protection and stirring, the reaction mixture was heated to 80 ° C. Subsequently, 0.02 g (0.007% by mass of perfluorooctyl vinyl ether) of Castaplatin catalyst was added via an injection pump. The reaction was maintained at 80 ° C for 4 hours. During the reaction, the FTIR at 2160 cm -1 The reaction was stopped when the peak intensity stabilized and no longer decreased, and almost completely disappeared.

[0090] After the reaction is complete, cool to room temperature. Add 10g of activated carbon powder, stir and adsorb for 1 hour, then filter to remove the activated carbon. Remove the toluene from the filtrate using a rotary evaporator at 50°C and a vacuum of -0.08 MPa, ultimately yielding a transparent, colorless to pale yellow, viscous liquid product. This is the sorbitol polyether-modified silicone surfactant described herein.

[0091] Performance testing and characterization:

[0092] Surface tension: The surface tension of the 0.1 wt% aqueous solution was measured using a platinum plate method and was 13.2 mN / m.

[0093] Water contact angle: The product was prepared into a 0.5wt% coating solution, applied on a glass substrate, and measured after curing. The water contact angle was 158.3° and the sliding angle was 7.5°.

[0094] Oil contact angle: Measured on the same coating using n-hexadecane as the oily liquid, the oil contact angle was 85.1°.

[0095] Elemental analysis: The results of elemental analysis showed that the carbon content was 42.1%, the hydrogen content was 6.8%, the oxygen content was 28.3%, the silicon content was 3.5%, and the fluorine content was 19.3%. This is highly consistent with the element ratio in the target molecular structure.

[0096] Structural confirmation: 1 H-NMR, 13 C-NMR and 19 The F-NMR spectra all showed the expected characteristic peaks, confirming the successful introduction and covalent bonding of the sorbitol skeleton, polyether chain, organosilicon linker, and perfluoroalkyl group. The FTIR spectra showed that the Si-H peak completely disappeared and the CF bond (1100-1300 cm) appeared. -1 ) and Si-C bonds (790-800cm -1 ) characteristic absorption.

[0097] Comparative Example 1: Preparation and properties of traditional polyether-modified silicone surfactants.

[0098] This comparative example is intended to demonstrate the performance of a polyether-modified silicone surfactant lacking a perfluoroalkyl segment, in order to compare the advantages of the perfluoroalkyl group introduced in the present invention.

[0099] Preparation of sorbitol polyether prepolymer (SP-OH):

[0100] As in Example 1, a sorbitol polyether prepolymer having a number average molecular weight of 1950 g / mol and a hydroxyl value of 300 mg KOH / g was prepared.

[0101] Silicon hydride functionalization (SP-SiH):

[0102] The same method as in Section 1.2 of Example 1 was used to prepare a sorbitol polyether intermediate product containing silicon-hydrogen bonds (SP-SiH).

[0103] Synthesis of traditional polyether modified silicone surfactants:

[0104] 400g of the SP-SiH intermediate product prepared above (about 0.8 moles of silicon-hydrogen bonds) was added to a 1L reactor. 600mL of dry toluene was added as a solvent. Under nitrogen protection and stirring, the reaction mixture was heated to 80°C. Subsequently, 0.02g of Castaplatin catalyst was added. The reaction was maintained at 80°C for 4 hours. Unlike Example 1, no perfluoroalkyl monomer containing an unsaturated bond was added in this step. On the contrary, in order to simulate the structure of traditional polyether silicone oil, we added a terminal vinyl polyether (polyethylene glycol monoallyl ether, Mn about 500) with a molar ratio of 1:1. After the reaction was completed, activated carbon adsorption and solvent removal were also carried out to obtain a light yellow transparent viscous liquid product. This is a traditional polyether-modified silicone surfactant.

[0105] Performance testing and characterization:

[0106] Surface tension: The surface tension of the 0.1 wt% aqueous solution was measured using a platinum plate method and was 21.8 mN / m.

[0107] Water contact angle: 0.5 wt% coating measured on glass substrate. Water contact angle is 98.5°, sliding angle cannot be measured (water droplet spreads directly).

[0108] Oil contact angle: measured on the same coating using n-hexadecane. The oil contact angle was 25.7°.

[0109] Example 2: Preparation and properties of high fluorine content sorbitol polyether-organosilicon-perfluorodecyl copolymer.

[0110] Preparation of SP-OH and SP-SiH:

[0111] The method was similar to that of Example 1, but the synthesis ratio of SP-OH was adjusted to a slightly higher hydroxyl number to accommodate more functionalized chains. Specifically, the molar ratio of sorbitol to total alkylene oxide was adjusted to 20:1. The Mn of SP-OH was 1500 g / mol, and the hydroxyl number was 350 mg KOH / g. The Si-H bond content of SP-SiH was 1.0 mol / 100 g.

[0112] Introduction of fluorinated alkyl (SP-Si-F) and synthesis of target product:

[0113] 400 g of the SP-SiH intermediate (approximately 1.0 mole of silicon-hydrogen bonds) and 500 g (approximately 0.9 mole) of 1H,1H,2H,2H-perfluorodecyl acrylate were added to a 1 L reactor. 700 mL of dry toluene was added as a solvent. The reaction mixture was heated to 90°C under nitrogen protection and stirring. Subsequently, 0.03 g of Castaplatin catalyst was added. The reaction was maintained at 90°C for 6 hours. After completion of the reaction, the product was adsorbed on activated carbon and the solvent was removed to obtain a transparent, viscous product.

[0114] Performance testing and characterization:

[0115] Surface tension: 11.5 mN / m measured in a 0.1 wt% aqueous solution.

[0116] Water contact angle: 165.2° for 0.5 wt% coating on glass substrate, with a sliding angle of 5.0°.

[0117] Oil contact angle: measured on the same coating using n-hexadecane: 92.8°.

[0118] Elemental analysis: fluorine content reaches 25.1%.

[0119] Weathering resistance testing and data analysis

[0120] In order to further verify the extreme environmental tolerance of the product of the present invention, we conducted a series of accelerated weathering tests on the product of Example 1 and the product of Comparative Example 1.

[0121] UV radiation resistance test: The products of Example 1 and Comparative Example 1 were prepared into 0.5 wt% solutions, evenly coated on a glass substrate, and cured at 40°C for 24 hours to form a uniform coating. Subsequently, the coating samples were placed in a UV aging chamber at a 254 nm UV radiation intensity of 0.8 W / m 2 Continuous irradiation was carried out under the conditions of temperature 50°C and humidity 70%. Samples were taken out regularly and their UV resistance was evaluated by the water contact angle decay rate.

[0122] Acid and Alkali Corrosion Resistance Test: Cured coating samples were immersed in a dilute sulfuric acid solution (pH 2) and a dilute sodium hydroxide solution (pH 12), respectively. After immersion at 25°C for 72 hours, the samples were removed, rinsed with deionized water, and dried. The water contact angle was measured again, and the decay rate was calculated.

[0123] Thermal and oxidative stability tests: Cured coating samples were placed in an air-circulating oven and aged at 150°C for 96 hours. After aging, the samples were removed and cooled to room temperature. The water contact angle was measured and the decay rate was calculated.

[0124] The following table summarizes the key performance parameters and weather resistance test results of the products of Example 1, Example 2 and Comparative Example 1. All contact angle decay rates are based on the initial contact angle.

[0125]

[0126] From the above data, it can be clearly seen that the sorbitol polyether modified silicone surfactant prepared by the present invention, particularly the product of Example 1 and Example 2, shows significant superiority in surface tension, super-hydrophobicity and super-oleophobicity.Its aqueous solution surface tension is much lower than traditional polyether modified silicone surfactant, and water contact angle and oil contact angle have reached the level of super-hydrophobicity and high oleophobicity. More importantly, in the accelerated aging test under the harsh environments such as simulated ultraviolet radiation, extreme pH value (acidic and alkaline) and high temperature oxidation, the contact angle decay rate of the product of the present invention is much lower than that of Comparative Example 1, which directly quantifies the anti-ultraviolet radiation, acid and alkali corrosion resistance and thermal oxidation stability of its significant improvement. This fully proves that the present invention, by introducing perfluoroalkyl section and constructing " fluorine-silicon-ether " ternary collaborative structure, has given surfactant excellent weather resistance and lasting functionality, overcomes the deep technical contradiction of single function and insufficient stability in the prior art.

[0127] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sorbitol polyether modified silicone surfactant, characterized in that: Its molecular structure comprises at least one sorbitol polyether hydrophilic segment, an organosilicon linking segment, and a perfluoroalkyl hydrophobic segment connected by covalent bonding, and the molecular structure can be represented by the following general formula: R 1 -[O-(C2H4O) x -(C3H6O) y -(C4H8O) z -Si(R 2 )2-(CH2) n -Rf] m (I) in: R 1 It is a sorbitol residue, whose structure is C6H7O(OH)5 or a structure in which some of its hydroxyl groups are substituted. The sorbitol residue serves as a molecular core scaffold, providing multiple reaction sites for connecting polyether chains; O-(C2H4O) x -(C3H6O) y -(C4H8O) z For the polyether segment O-(C2H4O) x -(C3H6O) y -(C4H8O)2, which is connected to the sorbitol residue through an ether bond or an ester bond, wherein (C2H4O) represents an ethylene oxide unit, (C3H6O) represents a propylene oxide unit, and (C4H8O) represents a butylene oxide unit; x, y, and z each independently represent the degree of polymerization of the corresponding alkylene oxide unit, and x, y, and z are non-negative integers, and the average value of their sum (x+y+z) ranges from 10 to 200; Si(R 2 ) 2 is an organosilicon unit, which is connected to the end or side chain of the polyether segment through a stable ether bond or silicon-carbon bond, wherein R 2 each independently represents a methyl group, an ethyl group or a phenyl group; (CH2) n is an alkylene linking segment, wherein n is an integer from 1 to 10, the alkylene linking segment is connected to the silicon atom of the organosilicon unit through a silicon-carbon bond, and is connected to Rf through a carbon-carbon bond, Rf is a perfluoroalkyl hydrophobic segment; Rf is a perfluoroalkyl hydrophobic segment, and its general formula is C p F 2p+1 , wherein p is an integer from 4 to 20; m represents the number of polyether-organosilicon-perfluoroalkyl chains connected to the sorbitol residue, and its value is an integer from 1 to 6.

2. The sorbitol polyether-modified silicone surfactant according to claim 1, wherein The sorbitol residue is connected to the oxygen atom of the polyether segment through at least one hydroxyl group to form an ether bond; When m is an integer less than 6, free hydroxyl groups are still retained on the sorbitol residue, and the retained free hydroxyl groups can further improve the hydrophilicity of the surfactant or provide additional reaction sites.

3. The sorbitol polyether-modified silicone surfactant according to claim 1 or 2, characterized in that: The total polymerization degree of the ethylene oxide units, propylene oxide units and butylene oxide units in the polyether segment is 20 to 150; wherein the proportion of the ethylene oxide unit is 50% to 90%, the proportion of the propylene oxide unit is 10% to 50%, and the proportion of the butylene oxide unit is 0% to 20%; The ethylene oxide units, propylene oxide units and butylene oxide units may be distributed in a statistically random, block or gradient manner.

4. The sorbitol polyether-modified silicone surfactant according to any one of claims 1 to 3, characterized in that: In the organosilicon unit, R 2 The organosilicon unit is specifically a dimethylsiloxane group [-Si(CH3)2O-], and the number of repeating units of the organosilicon linking segment is 1 to 5, that is, 1 to 5 organosilicon units can be connected to each polyether chain, and each organosilicon unit is connected to an alkylene linking segment and a perfluoroalkyl hydrophobic segment.

5. The sorbitol polyether-modified silicone surfactant according to any one of claims 1 to 4, characterized in that: The value of n in the alkylene linking segment is 2 or 3; the value of p in the perfluoroalkyl hydrophobic segment is 6 to 12, and the perfluoroalkyl group is C6F 13 、C8F 17 or C 10 F 21 .

6. A method for preparing a sorbitol polyether modified silicone surfactant, characterized in that: The following steps are involved: S1: preparing a sorbitol polyether prepolymer, wherein the prepolymer is a sorbitol core polyether having multiple hydroxyl ends; S2: functionalizing the sorbitol polyether prepolymer with a silicon-hydrogen group to form an intermediate product containing a silicon-hydrogen bond; S3: introducing a fluorinated alkyl group through a hydrosilylation reaction to synthesize the sorbitol polyether-modified silicone surfactant.

7. The method for preparing the sorbitol polyether-modified silicone surfactant according to claim 6, wherein: Said S1 comprises: Add sorbitol into a reaction kettle and heat to 90°C to 130°C under stirring; add 0.1% to 0.5% of the mass of sorbitol into a basic catalyst under the protection of inert gas; Slowly adding dropwise or passing ethylene oxide, propylene oxide or butylene oxide, wherein the ratio of the total molar amount of the alkylene oxide to the molar amount of sorbitol is 10:1 to 200:1; during the reaction process, the reaction temperature is maintained at 100° C. to 160° C., and the reaction pressure is controlled at 0.2 MPa to 0.8 MPa; The reaction is continued until the alkylene oxide monomer in the system is exhausted and the pressure is stable, and then the system is kept warm and aged for 1 to 3 hours. After the reaction is completed, the reaction product is neutralized and the pH of the system is adjusted to 6.0 to 7.0 using an acidic substance. After the catalyst salt is removed by filtration, the prepolymer is subjected to a dehydration and degassing treatment at 80° C. to 100° C. and a vacuum degree of -0.08 MPa to -0.095 MPa until the water content of the prepolymer is less than 0.1%.

8. The method for preparing the sorbitol polyether-modified silicone surfactant according to claim 6 or 7, characterized in that: The S2 includes: The sorbitol polyether prepolymer is placed in a reaction kettle and heated to 40° C. to 80° C. under an inert gas atmosphere; and a silicon-hydrogen bond chlorosilane is added at a molar ratio of 1:1 to 1.5:1 based on the hydroxyl content of each mole of the sorbitol polyether prepolymer; At the same time, an organic amine is added as an acid acceptor at a molar ratio of 1:1 to 1.2:1; the reactants are dissolved in an aprotic solvent; Under stirring conditions, slowly dropwise adding the mixed solution of the silicon-hydrogen bond chlorosilane and the organic amine, and maintaining the reaction temperature at 50° C. to 90° C. during the dropwise addition process; After the dropwise addition is completed, the reaction mixture is heated to 80° C. to 120° C. and kept warm for 2 to 6 hours until no hydrogen chloride gas escapes from the system; After the reaction is complete, the generated hydrochloride is removed by filtration, and the solvent is removed by rotary evaporation or vacuum distillation.

9. The method for preparing the sorbitol polyether-modified silicone surfactant according to any one of claims 6 to 8, characterized in that: The S3 includes: Adding the intermediate product containing a silicon-hydrogen bond and a perfluoroalkyl monomer containing an unsaturated bond in a molar ratio of 1:0.8 to 1:1.2 into a reaction kettle; dissolving the reactants in an aprotic solvent; Under inert gas protection and stirring conditions, the reaction mixture is heated to 60° C. to 100° C.; a platinum catalyst is added in an amount of 0.005% to 0.05% by weight of the unsaturated bond-containing perfluoroalkyl monomer; Maintaining the reaction at the temperature for 2 to 8 hours until the characteristic peak of the silicon-hydrogen bond in the system disappears in the Fourier transform infrared spectrum; After the reaction is completed, the catalyst and a small amount of unreacted monomers are removed by activated carbon adsorption or silica gel column chromatography, and then the solvent is removed by rotary evaporation or vacuum drying.

10. The method for preparing the sorbitol polyether-modified silicone surfactant according to any one of claims 6 to 9, characterized in that: The alkaline catalyst in S1 is potassium hydroxide or sodium methoxide, and the acidic substance is phosphoric acid or acetic acid; The silicon-hydrogen bond chlorosilane in S2 is dimethylchlorosilane or methylhydrogendichlorosilane, the organic amine is triethylamine or pyridine, and the aprotic solvent is toluene, xylene or tetrahydrofuran; The unsaturated bond-containing perfluoroalkyl monomer in S3 is 1H,1H,2H,2H-perfluorodecyl acrylate, perfluorohexyl vinyl ether or 1H,1H,2H,2H-perfluorooctyl vinyl ether, the platinum catalyst is a Castaplatin catalyst, and the aprotic solvent is toluene or ethyl acetate.

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