Perfluoropolyether modified silane compound containing double ether bonds, surface treating agent and application

Abstract

The invention discloses a perfluoropolyether modified silane compound containing double ether bonds, a surface treating agent and application, and relates to the technical field of fluorosilicone high polymer materials, the perfluoropolyether modified silane compound containing double ether bonds contains two different ether bond units (-CF2O-and-CF2CF2O-) in a perfluoropolyether main chain, the repeating unit numbers m and n of the two ether bond units are respectively integers of 1-40, the total repeating unit number m + n is 20-60, and m / n is 0.3-3; the tail end of a perfluoropolyether chain is connected with a trialkoxysilane group through an ether bond-alkyl-alkylene, and alkoxy in the trialkoxysilane group is C1-C4 alkyl. The structure endows the compound with excellent solubility, chain flexibility and low surface energy characteristics, so that a surface coating formed by the compound has excellent properties of high wear resistance, low oil stain residue, lasting hydrophobicity and oleophobicity, smoothness and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorosilicon high polymer materials, and particularly relates to a silane compound containing a double ether bond and modified by a perfluoropolyether, a surface treatment agent and application. BACKGROUND

[0002] When the perfluoropolyether-based silane compound is used for surface treatment of a substrate, a film layer with hydrophobic, oleophobic, antifouling and other properties can be formed on the surface of the substrate. On the one hand, the perfluoropolyether chain contains a large number of fluorine atoms, which has a low surface energy characteristic. On the other hand, the hydrolyzable alkoxysilane in the molecule can undergo dehydration condensation reaction with the silicon hydroxyl on the surface of the substrate to form a chemical bond and thus produce a durable and tough coating. Glass and ceramic substrates are widely used in the fields of smart phone cover plates, automotive center screens, building decoration panels, bathroom sanitary wares and the like. However, such substrates have the defects of easy adhesion of fingerprints and stains, and insufficient wear resistance.

[0003] The existing surface treatment agents mostly rely on a single perfluoro group or siloxane structure, and have the problems of poor durability of antifouling and anti-fingerprint, and insufficient wear resistance. At the same time, after construction, the excess coating of most treatment agents is difficult to clean and is easy to leave oil stains, affecting the cleanliness of the substrate surface. The perfluoropolyether compound has excellent antifouling potential due to its low surface energy, but the traditional perfluoropolyether structure lacks functional groups for strong bonding with the substrate, and the molecular solubility is poor, making it difficult to balance wear resistance and easy cleaning. In the prior art, the commercially available mainstream perfluoropolyether silane surface treatment agent has relatively excellent initial hydrophobic and oleophobic properties, but still has the problems of insufficient wear resistance and durability, low smoothness (high dynamic friction coefficient), and difficulty in cleaning the excess coating after construction, resulting in surface residual oil stains, which cannot fully meet the needs of high-end optical devices (such as smart phone screens and automotive center screens) for high wear resistance, low oil stain and durable anti-fingerprint. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a silane compound containing a double ether bond and modified by a perfluoropolyether, a surface treatment agent and application, and the specific technical scheme is as follows: A silane compound containing a double ether bond and modified by a perfluoropolyether, the structural formula of the silane compound containing a double ether bond and modified by a perfluoropolyether is shown as formula I: Formula I: Among them, Rf=CF3O(CF2O) m (CF2CF2O) n CF2-; m and n are integers of 1-40, and m+n=20-60, m / n=0.3-3; R1 is selected from any one of C1-C4 alkyl.

[0005] Preferably, R1 is methyl or ethyl.

[0006] The present application also provides a preparation method for preparing the bifurcated ether bond-containing perfluoropolyether-modified silane compound as described in any one of the above, comprising the following steps: S1. preparing a perfluoropolyether-modified intermediate, the general structure of which is shown in formula II: Formula II: S2. adding the perfluoropolyether-modified intermediate and an alkoxysilane into a solvent and reacting under the action of a catalyst to obtain the bifurcated ether bond-containing perfluoropolyether-modified silane compound.

[0007] Preferably: The catalyst is a platinum catalyst, and the amount of the catalyst is 20-100 ppm of the total mass of the reaction system; The solvent is selected from at least one of 1,3-bis(trifluoromethyl)benzene, hydrofluoroether, and perfluorohexane; The reaction temperature of step S2 is 50-100℃, and the reaction time is 3-8 hours.

[0008] Preferably, the platinum catalyst is selected from at least one of Karstedt catalyst, chloroplatinic acid catalyst, and platinum-divinyltetramethyldisiloxane complex.

[0009] Preferably, the preparation of the perfluoropolyether-modified intermediate in step S1 specifically comprises the following sub-steps: S11. mixing and reacting a perfluoropolyether alcohol with a haloacetic ester under alkaline conditions to obtain a perfluoropolyether ester compound; S12. hydrolyzing and acidifying the perfluoropolyether ester compound to obtain a perfluoropolyether carboxylic acid compound; S13. adding the perfluoropolyether carboxylic acid compound with an allyl Grignard reagent to obtain the perfluoropolyether-modified intermediate.

[0010] Preferably: In step S11, the base added in the alkaline conditions is selected from at least one of sodium hydroxide and potassium hydroxide; and the haloacetic ester is selected from at least one of methyl bromoacetate, ethyl bromoacetate, and tert-butyl bromoacetate; In step S12, the hydrolysis is carried out under high-temperature reflux conditions; and the acid used for acidification is selected from at least one of hydrochloric acid and sulfuric acid; In step S13, the allyl Grignard reagent is allyl magnesium bromide or allyl magnesium chloride, which is added dropwise, and the temperature is controlled at (0±0.5)℃ during the dropwise addition, and then the temperature is raised to room temperature for continuous reaction after the dropwise addition, and the reaction is quenched with saturated ammonium chloride solution after the reaction; Preferably: The reaction solvent in steps S11-S13 is at least one selected from 1,3-bis(trifluoromethyl)benzene, ethylene glycol dimethyl ether, and perfluorohexane; In step S11, a phase transfer catalyst is also added, and the phase transfer catalyst is at least one selected from tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium hydrogen sulfate; and the temperature of the mixed reaction is 30-50 DEG C.

[0011] The present application also provides a surface treatment agent containing the bisether bond-containing perfluoropolyether-modified silane compound according to any one of the preceding embodiments, and a fluorine solvent.

[0012] The present application also provides a use of the surface treatment agent according to any one of the preceding embodiments for coating an object surface to form a coating.

[0013] The bisether bond-containing perfluoropolyether-modified silane compound provided by the present application has the following beneficial effects: The abrasion resistance and fingerprint resistance of the coating are significantly improved: the water contact angle of the formed coating can reach 116-118 DEG, the n-hexadecane contact angle is above 75 DEG, and the water contact angle remains above 100 DEG after 15000-18000 times of friction with a 1 kg load steel wool, which is much better than the products of the prior art (usually significantly decreased after 8000-12000 times of friction), effectively solving the problems of insufficient abrasion resistance and poor fingerprint resistance of the prior art.

[0014] The smoothness and use experience are significantly improved: the dynamic friction coefficient of the coating is as low as 0.025-0.04, the surface touch is smooth, and fingerprints and oil stains are more easily wiped off.

[0015] The construction performance of low oil stain and easy cleaning is achieved: due to the excellent solubility of the bisether bond structure, the excess coating after spraying or evaporation construction is easily removed by a conventional cleaning process, the surface cleanliness is high, and the technical problem of residual oil stain after construction in the prior art is completely solved, making the product more suitable for large-scale production of high-end optical devices. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below.

[0017] Figure 1 A hydrophobic performance test diagram of a coating formed by the surface treatment agent provided in Embodiment 1 of the present application; Figure 2 A hydrophobic performance test diagram of a coating formed by the surface treatment agent provided in Comparative Example 2 of the present application; Figure 3NMR characterization chart of the bifluoroether bond-containing perfluoropolyether modified silane compound provided in the embodiments of the present application. DETAILED DESCRIPTION

[0018] In order to make the technical solution of the present application better understood by those skilled in the art, the present application will be described in detail below in conjunction with the drawings, and the description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present application.

[0019] The embodiments provide a bifluoroether bond-containing perfluoropolyether modified silane compound, and a structural formula of the bifluoroether bond-containing perfluoropolyether modified silane compound is shown as formula I: Formula I: wherein, Rf=CF3O(CF2O) m (CF2CF2O) n CF2-.

[0020] m and n are respectively integers from 1 to 40, and m+n=20-60, and m / n=0.3-3.

[0021] R1 is selected from any one of C1-C4 alkyl.

[0022] The bifluoroether bond-containing perfluoropolyether modified silane compound simultaneously introduces two different ether bond units (-CF2O- and -CF2CF2O-) in the perfluoropolyether chain segment, and controls the proportion (m / n=0.3-3) of the two units and the total polymerization degree (m+n=20-60), so that the molecular chain has moderate flexibility and polarity. The “bifluoroether bond” structure significantly improves the solubility of the compound in fluorine solvents and the fluidity of the molecular chain, while retaining the low surface energy characteristics of the perfluoropolyether chain. The terminal alkoxysilane group (-Si(OR1)3) can hydrolyze and condense on the surface of the substrate to form a firm Si-O-Si chemical bonding layer, and pin the perfluoropolyether chain to the surface of the substrate.

[0023] When the compound is used for surface treatment, the segment flexibility and moderate polarity brought by the bifluoroether bond make the perfluoropolyether chain more easily migrate and orderly arrange to the surface during the curing of the coating and the subsequent use process, forming a dense and smooth low surface energy fluorine layer; at the same time, the flexible chain segment can be locally rearranged when subjected to external force friction, relieving stress concentration, thereby maintaining the durability of the low energy state of the surface. In addition, the bifluoroether bond improves the solubility of the compound in the construction solvent, so that the excess coating is more easily dissolved and taken away by the solvent during cleaning, avoiding residue.

[0024] The bifluoroether bond-containing perfluoropolyether modified silane compound provided in the embodiments has the following beneficial effects: The abrasion resistance and anti-fingerprint durability of the coating are significantly improved: the water contact angle of the formed coating can reach 116°-118°, the n-hexadecane contact angle is more than 75°, and the water contact angle is still more than 100° after 15000-18000 times of friction of 1 kg load steel wire wool, which is much better than the prior art product (usually significantly decreased after 8000-12000 times), effectively solving the problems of insufficient abrasion resistance and poor anti-fingerprint durability of the prior art.

[0025] The smoothness and use experience are significantly improved: the dynamic friction coefficient of the coating is as low as 0.025-0.04, the surface touch is smooth, and the fingerprints and oil stains are more easily slipped or wiped clean.

[0026] The construction performance of low oil stain and easy cleaning is realized: due to the excellent solubility brought by the double ether bond structure, the excess coating after spraying or evaporation construction can be easily removed by conventional cleaning process, the surface cleanliness is high, and the technical difficulties of difficult cleaning and easy residual oil stain after construction in the prior art are completely solved, so that the product is more suitable for large-scale production of high-end optical devices.

[0027] Further, R 1 is methyl or ethyl.

[0028] The embodiment also provides a preparation method for preparing the double-ether-bond-containing perfluoropolyether modified silane compound as described in any one of the above. S1. preparing a perfluoropolyether modified intermediate, the general structure of the perfluoropolyether modified intermediate is shown as formula II: Formula II: S2. adding the perfluoropolyether modified intermediate and alkoxysilane into a solvent, and reacting under the action of a catalyst to obtain the double-ether-bond-containing perfluoropolyether modified silane compound.

[0029] Specifically, the method takes perfluoropolyether alcohol as a starting material, first introduces an allyl double bond through etherification and Grignard reaction to obtain an allyl-terminated intermediate with high activity. The intermediate structure retains the double ether bond characteristics of the perfluoropolyether chain, and the allyl double bond activity is moderate, which facilitates subsequent precise hydrosilylation. Subsequently, under the action of a platinum catalyst (such as Karstedt catalyst), the silicon-hydrogen bond and the carbon-carbon double bond are efficiently added to form a stable C-Si bond connection, avoiding the side reactions (such as hydrolysis overreaction or chain degradation) that may occur in traditional methods. In particular, the hydrosilylation reaction of step S2 can be carried out under argon protection (inert atmosphere), which can effectively exclude oxygen and moisture in the air, prevent the platinum catalyst from being oxidized and deactivated, avoid premature hydrolysis of alkoxysilane or oxidative degradation of perfluoropolyether chain, and thus ensure the selectivity, yield and product purity of the reaction. The whole process has mild reaction conditions (50-100℃), simple steps, is green and pollution-free, and the high selectivity of hydrosilylation ensures the high purity and structural integrity of the target compound.

[0030] Further: The catalyst is a platinum catalyst, and the amount is 20-100 ppm of the total mass of the reaction system.

[0031] The solvent is selected from at least one of 1,3-bis(trifluoromethyl)benzene, hydrofluoroether, and perfluorohexane.

[0032] The reaction temperature of step S2 is 50-100℃, and the reaction time is 3-8 hours.

[0033] Further, the platinum catalyst is selected from at least one of Karstedt catalyst, chloroplatinic acid catalyst, and platinum-divinyltetramethylsiloxane complex.

[0034] Further, the preparation of the perfluoropolyether modified intermediate in step S1 specifically includes the following sub-steps: S11. Under alkaline conditions, perfluoropolyether alcohol is mixed and reacted with haloacetic ester to obtain a perfluoropolyether ester compound.

[0035] S12. The perfluoropolyether ester compound is hydrolyzed and acidified to obtain a perfluoropolyether carboxylic acid compound.

[0036] S13. The perfluoropolyether carboxylic acid compound is subjected to addition reaction with allyl Grignard reagent to obtain a perfluoropolyether modified intermediate.

[0037] Specifically, the sub-step sequence takes perfluoropolyether alcohol (weight average molecular weight preferably 3800-4500, more preferably 4000; the perfluoropolyether alcohol is a linear polymer formed by photooxidation of tetrafluoroethylene under the action of ultraviolet rays) as the starting material, first introduces a carboxylate group into the end of the perfluoropolyether chain through an alkali-promoted etherification reaction to form an ester-protected intermediate; then, through basic hydrolysis and acidification deprotection, a perfluoropolyether carboxylic acid compound with higher activity is obtained; finally, using the strong nucleophilicity of Grignard reagent, an addition reaction with the carboxylic acid compound is carried out to efficiently introduce an allyl double bond to form a perfluoropolyether modification intermediate (Formula II) with an allyl group at the end.

[0038] The allyl Grignard reagent (allyl magnesium bromide or allyl magnesium chloride) in step S13 is highly active and easily reacts with moisture, oxygen or carbon dioxide in the air to generate byproducts, resulting in a decrease in yield or reaction failure. In order to ensure that the reaction is efficiently and selectively carried out, step S13 needs to be carried out in an inert atmosphere (such as argon or nitrogen protection), which is a well-known common sense in the operation of organic magnesium compounds (Grignard reagent) in organic chemistry. Through the protection of inert atmosphere, the interference of moisture and oxygen can be effectively excluded, the activity of Grignard reagent is ensured, and the addition reaction is successfully completed, while avoiding the potential degradation of perfluoropolyether chain under strong alkaline conditions.

[0039] The entire sub-step sequence is reasonably designed and the reaction conditions are mild. The step-by-step protection-deprotection-addition strategy avoids the side reactions that may be caused by directly introducing a double bond on the perfluoropolyether alcohol, ensuring efficient introduction of the allyl group and complete preservation of the diether bond structure.

[0040] Further: In step S11, the base added under alkaline conditions is selected from at least one of sodium hydroxide (a 20%-50% aqueous solution of sodium hydroxide is added, preferably a 50% aqueous solution of sodium hydroxide), and potassium hydroxide; the haloacetate is selected from at least one of methyl bromoacetate, ethyl bromoacetate, and tert-butyl bromoacetate.

[0041] In step S12, the hydrolysis is carried out under high-temperature reflux conditions; the acid used for acidification is selected from at least one of hydrochloric acid and sulfuric acid.

[0042] In step S13, the allyl Grignard reagent is allyl magnesium bromide or allyl magnesium chloride, which is added by dripping, and the temperature is controlled at (0±0.5) ℃ during dripping. After dripping, the temperature is raised to room temperature for continued reaction, and after reaction, saturated ammonium chloride solution is used for quenching.

[0043] Specifically, the limitation ensures the optimal conditions of each sub-step: in S11, the strong base promotes the formation of perfluoropolyether alcohol oxygen anion, and the halogen atom of the easily substituted halogen acetate; to achieve efficient etherification and subsequent hydrolysis, the strategy of adding base twice is often used in actual operation-the first time (small amount) is used for the initial etherification reaction to generate ester intermediates, and the second time (higher concentration) is used after the esterification is completed to generate carboxylate by subsequent high-temperature reflux hydrolysis of ester groups. The known operation of adding base twice can effectively avoid side reactions (such as chain degradation or incomplete ester hydrolysis) caused by excessive addition of base at one time, while ensuring complete hydrolysis. S12 high-temperature reflux accelerates the breaking of ester bond, and acidification converts carboxylate into free carboxylic acid to improve the subsequent addition activity. S13 low-temperature dropwise addition controls the exothermic reaction of Grignard reagent to avoid local overheating; room temperature continues to react to ensure complete addition; saturated ammonium chloride gently quenches the remaining Grignard reagent to prevent excessive damage to the product. These detailed limitations make the reaction process safer, controllable, and maximize the preservation of the double ether bond structure of the perfluoropolyether chain.

[0044] Further, The reaction solvents in steps S11-S13 are selected from at least one of 1,3-bis(trifluoromethyl)benzene, ethylene glycol dimethyl ether, and perfluorohexane.

[0045] In step S11, a phase transfer catalyst is also added, and the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium hydrogen sulfate. The temperature of the mixed reaction is 30-50°C.

[0046] Among them, the fluorine solvent (such as 1,3-bis(trifluoromethyl)benzene) is highly compatible with the perfluoropolyether chain, ensuring good dissolution of raw materials and intermediates; ethylene glycol dimethyl ether as a cosolvent further improves the system fluidity. Step S11 is a typical two-phase reaction (alkali aqueous solution and organic phase), and the addition of a phase transfer catalyst effectively transfers hydroxyl ions or alcohol oxygen anions in the water phase to the organic phase, promoting efficient nucleophilic substitution reaction, while reducing the reaction temperature requirement. The mild temperature of 30-50°C avoids the potential degradation of the perfluoropolyether chain at high temperature.

[0047] Further, according to one preferred embodiment of the present embodiment, the preparation method of the double-ether-bond-containing perfluoropolyether-modified siloxane compound comprises the following steps: Step one: In a four-necked flask equipped with a stirrer, a reflux condenser, and a dropping funnel, the perfluoropolyether alcohol is dissolved in 1,3-bis(trifluoromethyl)benzene and ethylene glycol dimethyl ether, stirred at room temperature, then sodium hydroxide solution is added and stirred for 1 hour, then methyl bromoacetate and a phase transfer catalyst are added to the reaction bottle, stirred at 50°C for 3 hours, then cooled to room temperature, and then sodium hydroxide solution is added, hydrolyzed under reflux at 110°C, and purified by acidification with hydrochloric acid to obtain a perfluoropolyether compound (M1).

[0048] The perfluoropolyether compound M1 was dissolved in 1,3-bis(trifluoromethyl)benzene, and allyl magnesium bromide was slowly added dropwise through a dropping funnel at 0°C with stirring for 2 hours. The mixture was then heated to 50°C and stirred for 5 hours, followed by quenching with saturated ammonium chloride. The mixture was then extracted multiple times with perfluorohexane and methanol to obtain the lower layer, which was then removed by vacuum distillation to remove volatile components, yielding a colorless and transparent product of formula II.

[0049] Step Two: Under argon protection, the perfluoropolyether modified intermediate containing diether bonds shown in Formula II was mixed with 1,3-bis(trifluoromethyl)benzene and alkoxysilane, and a caster catalyst was added. The mixture was reacted at 80°C for 4 hours, and the product Formula I was obtained by methanol extraction and purification.

[0050] Since the di-ether-bonded perfluoropolyether-based modified silane compound obtained in this embodiment is a specific di-ether-bonded perfluoropolyether-based bissilane compound, it is suitable for surface treatment agents. The surface treatment agent may contain one or more of the perfluoropolyether-based modified silane compounds described above, as well as a liquid medium such as an organic solvent. A wide range of organic solvents are acceptable, provided they do not react with the compound of this embodiment and can dissolve it well. The organic solvent may include fluorinated solvents, fluorinated haloalkanes, hydrofluoroethers, etc., or combinations of different solvents. The concentration of the perfluoropolyether-based modified silane compound in the surface treatment agent can be adjusted as needed, preferably 0.01~30wt%, more preferably 0.05~20wt%, and more preferably 10~20wt%; different concentrations can be selected depending on the coating process.

[0051] This embodiment also provides a surface treatment agent containing a perfluoropolyether modified silane compound with diether bonds as described above, and a fluorinated solvent.

[0052] The surface treatment agent takes the PFPE silane compound with the specific diether bond structure as the core active ingredient, is dissolved in a fluorine solvent (such as hydrofluoroether Novec HFE-7200) with excellent compatibility, and forms a stable and clear solution. The content of the diether bond-containing perfluoropolyether modified silane compound is 0.01-30 wt%, preferably 0.05-20 wt%, and more preferably 5-15 wt%. The content range is designed based on the coating process and performance balance: a low concentration (0.05-5 wt%) is suitable for dry processes such as vacuum evaporation, forming an ultrathin nanoscale coating (5-10 nm) to ensure optical transparency; a higher concentration (10-20 wt%) is suitable for wet processes such as spraying or dipping, providing a thicker protective layer (10-25 nm) to enhance wear resistance. The diether bond structure endows the compound with excellent solubility and fluidity, allowing it to disperse uniformly in the fluorine solvent without precipitation; the low surface tension, low boiling point, and volatility of the fluorine solvent ensure good substrate wettability and rapid film formation during application.

[0053] After being applied to the surface of the substrate, the silane groups hydrolyze and condense to bind to the substrate, and the diether bond perfluoropolyether chain migrates to the air side and arranges in order, forming a dense, smooth, and low-surface-energy fluorinated protective layer. The chain flexibility and moderate polarity brought by the diether bond further promote the rearrangement and self-healing ability of the fluorine chain on the surface, improving the durability of the coating.

[0054] Further, a fluorine alkyl modified benzophenone derivative (such as 4-(perfluorobutyloxy)-2-hydroxybenzophenone) can also be added as an auxiliary additive, with an addition amount of 0.1-2 wt% (preferably 0.3-1 wt%). The preparation process of the derivative is as follows: taking 2,4-dihydroxybenzophenone as the starting material, adding potassium carbonate or sodium hydroxide (1.1-1.5 equivalents) and a phase transfer catalyst (such as tetrabutylammonium bromide, 0.1 equivalent) in a fluorine solvent (such as 1,3-bis(trifluoromethyl)benzene), slowly adding perfluorobutyl iodine or perfluorobutyl bromine (1.1 equivalent) at 50-80°C, stirring under argon protection for 8-24 hours; after the reaction is completed, water quenching, fluorine solvent extraction, drying, reduced pressure distillation or column chromatography purification to obtain the target compound. The perfluoroalkoxy chain of the derivative is highly compatible with the PFPE silane, and the benzophenone core provides high-efficiency UV absorption and potential photocrosslinking ability. By adding the fluorine alkyl modified benzophenone derivative, the following technical effects can be achieved: UV weather resistance is significantly improved, yellowing resistance is excellent, wear resistance is further increased, and the core anti-fingerprint performance is basically unchanged, solving the aging problem of the prior art in strong light environment and expanding the outdoor application scenarios.

[0055] The embodiment also provides an application of coating an object surface with the surface treatment agent of any one of the above.

[0056] In particular, the application utilizes the excellent film-forming properties of the surface treatment agent prepared by the present embodiment to form a nanoscale ultra-thin coating (preferably 1-25 nm thick, more preferably 5-15 nm thick) on the surface of various substrates by conventional processes such as vacuum evaporation, spraying, dipping, spin coating, etc. After the coating is cured (80-150°C heating for 30 min, optionally with UV assistance), the silane groups form covalent Si-O-Si bonds with the substrate surface silanol groups, firmly anchoring the diether-linked perfluoropolyether chain; the flexibility and low surface energy properties of the chain segments cause the fluorine atoms to be concentrated on the outermost layer, forming a highly hydrophobic and oleophobic barrier. At the same time, the moderate polarity and flexibility of the diether linkage endow the coating with stress buffering and self-healing capabilities; under friction or environmental stress, the segments can rearrange locally, maintaining the low-energy state of the surface. If the surface treatment agent contains fluoralkyl-modified benzophenone derivatives, it further provides UV protection and light crosslinking, enhancing long-term stability.

[0057] Optional objects include, but are not limited to: Electronic display devices: smartphone cover glass, tablet touch screen, notebook display screen, smartwatch surface, car navigation screen, car central control touch screen.

[0058] Optical elements: camera lens, AR / VR glasses lens, optical instrument protective glass.

[0059] Building and home: marble countertop, bathroom ceramic sanitary ware (such as toilet, washbasin), kitchen glass panel, building curtain wall glass.

[0060] Others: medical device surface, solar panel protective layer, aerospace transparent parts.

[0061] The following provides specific examples, which can enable those skilled in the art to have a more comprehensive understanding of the present application, but in no way limit the present application.

[0062] Example 1 Synthesis of diether-linked perfluoropolyether-modified silane compound of formula A1 according to the following steps: Step 1: Into a 250 mL three-necked round-bottom flask equipped with a stirrer, 20 g of an average composition of CF3(OCF2CF2) m (OCF2) nPerfluoropolyether alcohol (number average molecular weight 3500~4000) of OCF2CH2OH (m+n=20-60), 30 mL of 1,3-bis(trifluoromethyl)benzene and 10 mL of ethylene glycol dimethyl ether, 5.4 g of 50% sodium hydroxide aqueous solution, stirring at room temperature for 3 hours. Then add 7.2 mL of methyl bromoacetate, 0.84 g of tetrabutylammonium bromide to the reaction bottle in turn, and stir at 50°C for 5 hours. Lower to room temperature, add 20 mL of acetonitrile, and after adjusting to acidic with hydrochloric acid, add 60 mL of perfluorohexane and stir. Remove the upper liquid. Finally, distill under reduced pressure to obtain 20.5 g of colorless transparent product.

[0063] In a 250 mL four-necked flask equipped with a dropping funnel, thermometer and stirrer, 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, 2.6 mL of allyl magnesium bromide solution were dissolved and slowly added to the above reaction system at 0°C with a dropping funnel, then warmed to 80°C and stirred for 4 hours, then added 10 mL of saturated ammonium chloride solution. Add 80 mL of perfluorohexane, extract with 35 mL of methanol three times, collect the lower layer, and concentrate by rotary evaporation to obtain a perfluoropolyether-based compound with an olefin bond at the end, the performance characterization of which is shown in Table 1 below: Table 1: Performance characterization of perfluoropolyether-based compounds Step 2: In a 250 mL four-necked flask equipped with a dropping funnel, thermometer and stirrer, 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, 10 mL of ethylene glycol dimethyl ether, 5.4 g of 50% sodium hydroxide aqueous solution were dissolved and stirred at room temperature for 3 hours. Then add 6 mL of allyl bromide, 0.84 g of tetrabutylammonium bromide to the reaction bottle in turn, and stir at 50°C for 5 hours. Lower to room temperature, add 20 mL of acetonitrile, and after adjusting to acidic with hydrochloric acid, add 60 mL of perfluorohexane and stir. Remove the upper liquid. Finally, distill under reduced pressure to obtain 20.5 g of colorless transparent product, a perfluoropolyether-based compound with an olefin bond at the end.

[0064] Step 3: Under argon protection, in a three-necked flask equipped with a thermometer, stirrer and condenser, 20 g of the above compound, 30 mL of dry 1,3-bis(trifluoromethyl)benzene, 18 g of trimethoxysilane were dissolved and stirred to clarify, heated to 80°C under argon environment, added 2.4 g of Karstedt catalyst toluene solution dropwise, reacted for 24 h under argon environment, concentrated by rotary evaporation to obtain 18 g of light yellow perfluoropolyether modified silane compound (A1).

[0065] The compound A1 thus obtained was prepared into a 20% mass concentration with hydrofluoroether (manufactured by 3M, Novec HFE7200) as a surface treatment agent (1), and the surface treatment agent was vacuum-deposited onto the chemically strengthened glass. The vacuum pressure was less than 4 x 10 -3 Under a vacuum pressure of less than 4 x 10

[0066] Example 2 A perfluoropolyether-modified silane compound A2 was synthesized according to the following procedure: Step 1: A 250 mL three-necked round-bottom flask equipped with a stirrer was charged with 20 g of a perfluoropolyether alcohol having an average composition of CF3(OCF2CF2) m (OCF2) n A 250 mL three-necked round-bottom flask equipped with a stirrer was charged with 20 g of a perfluoropolyether alcohol having an average composition of CF3(OCF2CF2)

[0067] A 250 mL four-necked flask equipped with a dropping funnel, a thermometer, and a stirrer was charged with 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, and 2.6 mL of an allylmagnesium bromide solution, and the reaction system was slowly added with the dropping funnel at 0°C, and then warmed to 80°C and stirred for 4 hours. Then, 10 mL of a saturated ammonium chloride solution was added, and 80 mL of perfluorohexane was added, and the mixture was extracted with 35 mL of methanol three times. The lower layer was collected and concentrated by rotary evaporation to obtain a perfluoropolyether compound having an olefin bond at the end.

[0068] Step 2: In a 250 mL three-necked flask equipped with a dropping funnel, a thermometer and a stirrer, 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, 10 mL of ethylene glycol dimethyl ether and 5.4 g of 50% sodium hydroxide aqueous solution were stirred at room temperature for 3 hours. Then, 6 mL of allyl bromide and 0.84 g of tetrabutylammonium bromide were added to the flask, and the mixture was stirred at 50°C for 5 hours. After the mixture was cooled to room temperature, 20 mL of acetonitrile was added, and the mixture was acidified with hydrochloric acid. Then, 60 mL of perfluorohexane was added to the mixture, and the mixture was stirred. The upper layer was removed. Finally, the colorless transparent product was obtained by distillation under reduced pressure. Thus, 20.5 g of a perfluoropolyether compound A2 having an olefinic bond at the terminal was obtained.

[0069] Step 3: In a three-necked flask equipped with a thermometer, a stirrer and a condenser, 20 g of the above compound, 30 mL of dry 1,3-bis(trifluoromethyl)benzene and 18 g of triethoxysilane were stirred to dissolve the mixture. The mixture was heated to 80°C under argon atmosphere, and 2.4 g of Karstedt's catalyst dissolved in toluene was added dropwise. The mixture was reacted for 24 hours under argon atmosphere. The mixture was concentrated by rotary evaporation. Thus, 17.8 g of a yellowish perfluoropolyether-modified silane compound was obtained.

[0070] The compound A2 obtained by the synthesis was mixed with hydrofluoroether (manufactured by 3M Company, Novec HFE7200) to prepare a 20% mass concentration of a surface treatment agent (2). The above surface treatment agent was vacuum-deposited onto chemically strengthened glass. Under a vacuum pressure of less than 4 x 10 -3 Pa, silicon dioxide was deposited on the chemically strengthened glass to form a silicon dioxide film by an electron beam deposition method at a thickness of 10 nm. Then, the compound was vacuum-deposited on each piece of the chemically strengthened glass at a thickness of about 8 to 10 nm. Then, the chemically strengthened glass with the deposited film was left to stand in an environment of 50% humidity and 150°C for 30 minutes to cure the film, thereby forming a surface treatment layer.

[0071] Example 3 The perfluoropolyether-modified silane compound A3 was synthesized according to the following procedure: In a 250 mL three-necked flask equipped with a stirrer, 20 g of a perfluoropolyether compound having an average composition of CF3(OCF2CF2) m (OCF2) nA perfluoropolyether alcohol (number average molecular weight: 3500-4000) of OCF2CH2OH (m+n=20-60), 30 mL of 1,3-bis(trifluoromethyl)benzene, and 10 mL of ethylene glycol dimethyl ether, 5.4 g of a 50% sodium hydroxide aqueous solution, were stirred at room temperature for 3 hours. Then, 7.2 mL of methyl bromoacetate and 0.84 g of tetrabutylammonium bromide were sequentially added to the reaction vessel, and stirring was performed at 50°C for 5 hours. After being allowed to decrease to room temperature, 20 mL of acetonitrile was added, and the mixture was made acidic with hydrochloric acid. Then, 60 mL of perfluorohexane was added, and stirring was performed. The upper layer was removed. Finally, a colorless transparent product 20.5 g was obtained by distillation under reduced pressure.

[0072] In a 250 mL four-necked flask equipped with a dropping funnel, a thermometer, and a stirrer, 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, and 2.6 mL of an allylmagnesium bromide solution were dissolved, and the mixture was slowly added dropwise to the above reaction system at 0°C using a dropping funnel. Then, the temperature was increased to 80°C, and stirring was performed for 4 hours. Then, 10 mL of a saturated ammonium chloride solution was added. Then, 80 mL of perfluorohexane was added, and extraction was performed three times with 35 mL of methanol. The lower layer was collected, and rotary evaporation was performed to obtain a perfluoropolyether-based compound having an olefin bond at the terminal.

[0073] Step 2: In a three-necked flask equipped with a thermometer, a stirrer, and a condenser, 20 g of the above compound, 30 mL of dry 1,3-bis(trifluoromethyl)benzene, and 12 g of trimethoxysilane were stirred and dissolved to be clear. Then, 2.4 g of a toluene solution of Karstedt catalyst was added dropwise under an argon atmosphere, and the mixture was heated to 80°C. Then, the reaction was performed for 24 hours under an argon atmosphere. Then, rotary evaporation was performed to obtain a light yellow perfluoropolyether-modified silane compound 19 g (A3).

[0074] The obtained compound A3 was mixed with hydrofluoroether (manufactured by 3M Company, Novec HFE7200) to prepare a surface treatment agent (3) having a mass concentration of 20%. The above surface treatment agent was vacuum-deposited onto chemically strengthened glass. In a vacuum pressure of less than 4 x 10 -3 Pa, silicon dioxide was first deposited onto the chemically strengthened glass to form a silicon dioxide film by an electron beam deposition method at a thickness of 10 nm. Then, the compound was vacuum-deposited onto each piece of chemically strengthened glass at a thickness of about 8 to 10 nm. Then, the chemically strengthened glass on which the deposited film was attached was left to stand in an environment of 50% humidity and 150°C for 30 minutes to be cured, so that a surface treatment layer was formed.

[0075] Comparative Example 1 A perfluoropolyether-modified silane compound A4 was synthesized according to the following steps: Step 1: Add 20g of the mixture with an average composition of HOCH2CF2(OCF2CF2) to a 250mL three-necked round-bottom flask equipped with a stirrer. m (OCF2) n A perfluoropolyether alcohol (number average molecular weight 3500-4000) of OCF₂CH₂OH (m+n=20-60), 30 mL of 1,3-bis(trifluoromethyl)benzene, 10 mL of ethylene glycol dimethyl ether, and 10.8 g of 50% sodium hydroxide aqueous solution were stirred at room temperature for 3 hours. Then, 14.4 mL of methyl bromoacetate and 1.7 g of tetrabutylammonium bromide were added sequentially to the reaction flask, and the mixture was stirred at 50 °C for 5 hours. After cooling to room temperature, 20 mL of acetonitrile was added, and the solution was adjusted to acidity with hydrochloric acid. Then, 60 mL of perfluorohexane was added, and the mixture was stirred. The supernatant was removed. Finally, 20 g of a colorless and transparent product was obtained by vacuum distillation.

[0076] In a 250 mL four-necked flask equipped with a dropping funnel, thermometer, and stirrer, 20.0 g of the above product and 30 mL of 1,3-bis(trifluoromethyl)benzene were added to dissolve the product. 5.2 mL of allyl magnesium bromide solution was added dropwise to the reaction system using a dropping funnel at 0 °C. The mixture was then heated to 80 °C and stirred for 4 hours. 10 mL of saturated ammonium chloride solution was added. 80 mL of perfluorohexane was added, and the mixture was extracted three times with 35 mL of methanol. The lower layer was collected and concentrated by rotary evaporation to obtain a perfluoropolyether compound with terminal olefin bonds.

[0077] Step 2: In a 250 mL four-necked flask equipped with a dropping funnel, thermometer, and stirrer, 20.0 g of the above product, 30 mL of 1,3-bis(trifluoromethyl)benzene, 10 mL of ethylene glycol dimethyl ether, and 5.4 g of 50% sodium hydroxide aqueous solution were added, and the mixture was stirred at room temperature for 3 hours. Then, 6 mL of allyl bromide and 1.7 g of tetrabutylammonium bromide were added sequentially to the reaction flask, and the mixture was stirred at 50 °C for 5 hours. The mixture was cooled to room temperature, 20 mL of acetonitrile was added, and the solution was adjusted to acidity with hydrochloric acid. Then, 60 mL of perfluorohexane was added, and the mixture was stirred. The supernatant was removed. Finally, the mixture was distilled under reduced pressure to obtain 20.5 g of a colorless, transparent product, yielding a perfluoropolyether compound with terminal olefin bonds.

[0078] Step 3: Under argon protection, 20g of the above compound, 30mL of dry 1,3-bis(trifluoromethyl)benzene, and 36g of trimethoxysilane were stirred, dissolved, and clarified in a three-necked flask equipped with a thermometer, a stirrer, and a condenser. The mixture was heated to 80°C under argon protection, and 4.8g of a toluene solution of the caster catalyst was added dropwise. The reaction was carried out under argon protection for 24 hours, and the mixture was concentrated by rotary evaporation to obtain 19g of a pale yellow perfluoropolyether modified silane compound (A4).

[0079] The synthesized compound A4 was prepared with hydrofluoroether (manufactured by 3M, Novec HFE7200) to a concentration of 20% by mass as a surface treatment agent (4). This surface treatment agent was then deposited onto chemically strengthened glass using vacuum deposition. The vacuum pressure was less than 4 × 10⁻⁶. -3 Under Pa conditions, silicon dioxide is first deposited onto chemically strengthened glass with a thickness of 10 nm using electron beam deposition to form a silicon dioxide film. Then, a compound with a thickness of approximately 8-10 nm is deposited on each piece of chemically strengthened glass using vacuum deposition. Finally, the chemically strengthened glass with the deposited film is placed in an environment of 50% humidity and 150°C for 30 minutes to cure, thereby forming a surface treatment layer.

[0080] Comparative Example 2 Except for using the commercially available surface treatment agent 1 described below to replace the surface treatment agent prepared with the above compounds, the surface treatment layer is formed in the same manner as described in Example 1.

[0081] Comparison surface treatment agent 1: Optool UD 509 (produced by Daikin Industries, Ltd.) Comparative Example 3 Except for using the commercially available surface treatment agent 2 described below to replace the surface treatment agent prepared with the above compounds, the surface treatment layer is formed in the same manner as described in Example 1.

[0082] Comparison surface treatment agent 2: Optool DSX-E (produced by Daikin Industries, Ltd.) Comparative Example 4 A perfluoropolyether-modified silane derivative, with the structural formula shown below, is used to form a surface treatment layer using the same method as described in Example 1.

[0083] The surface treatment layers prepared in Examples 1-3 and Comparative Examples 1-4 were tested using the following methods, and the test results are shown in Tables 2-5.

[0084] 1. Hydrophobic and oleophobic test The static contact angle of water with the above-mentioned surface treatment layer was measured. The static contact angle of water was measured using a contact angle measuring device (Beijing HARKE-DWA) at 25°C and 65% humidity with 1 μL of water.

[0085] 2. Determination of smoothness The coefficient of kinetic friction relative to the paper (Dabé) was tested using a friction coefficient meter (Jinan Sike Testing Technology Co., Ltd.) under the following conditions.

[0086] Contact area: 63mm × 63mm; Load: 200g Linear velocity: 100 mm / min travel: 30mm 3. Wear resistance test The water contact angle of the surface treatment layer after friction was evaluated using a friction testing machine (Taber, 5900) under the following conditions. The water contact angle was measured after 1000 cycles of friction each time (the test was terminated when the water contact angle was less than 100 degrees or when the abrasive was damaged after 20,000 cycles).

[0087] (1) Steel wool abrasion resistance test Steel wool: BONSTAR#0000 Load: 1 kg / cm 2 Travel distance: 40mm Movement speed: 60 rpm (2) Rubber abrasion resistance test Eraser: Minoan MB006004, 6.0mm Load: 1kg Travel distance: 40mm Movement speed: 60 rpm 4. Oil stain cleaning test After the coated glass is cleaned with a flatbed cleaning machine, the surface oil residue is observed and evaluated using a strong flashlight.

[0088] Cleanliness levels are categorized into four standards: clean, slightly oily, moderately oily, and very heavily oily. As can be seen from the above embodiments and comparative examples, the surface treatment agent prepared using the diether-bonded perfluoropolyether-modified silane compound of this embodiment gives the glass substrate surface excellent anti-fouling, anti-fingerprint, and wear-resistant properties, and also provides excellent smoothness to enhance the user experience. Furthermore, it facilitates easy cleaning of industrially produced glass surfaces, resulting in superior cleanliness. Its overall performance surpasses that of mainstream commercially available products. Moreover, the preparation method of the compound in this embodiment is simple, easy to operate, and suitable for mass production.

[0089] Comparing Example 1 and Comparative Example 4, it can be seen that Example 1 uses more ether bonds than Comparative Example 4. Example 1 has better cleaning performance. Examples 1 and 2 have better abrasion resistance than Example 3, possibly because the bissiloxane mechanism increases the adhesion to the substrate. Example 1 has better abrasion resistance and smoothness than Comparative Example 1, which is related to the more mobile and orderly arrangement of the single-ended perfluoropolyether segments. It can have a wider range of applications in the field of high-end optical components.

[0090] Please see Figure 1 and Figure 2 The figures show a comparison of the hydrophobicity of the coating prepared in Example 1 and a commercially available coating (Comparative Example 3). It can be seen from the figures that the static water droplet angle of the coating prepared in Example 1 (118°) is significantly greater than that of Comparative Example 3 (114°), indicating that the product treated in Example 1 has better hydrophobic properties.

[0091] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be within the scope of protection of the present invention.

Claims

1. A perfluoropolyether-modified silane compound containing diether bonds, characterized in that, The structural formula of the perfluoropolyether modified silane compound containing diether bonds is shown in Formula I: Formula I: in, Rf=CF3O(CF2O) m (CF2CF2O) n CF2-; m and n are integers from 1 to 40, and m+n=20~60, m / n=0.3~3; R1 is selected from any one of C1 to C4 alkyl groups.

2. The perfluoropolyether-modified silane compound containing diether bonds according to claim 1, characterized in that, R1 is methyl or ethyl.

3. A preparation method, characterized in that, The method for preparing the perfluoropolyether-modified silane compound containing diether bonds as described in claim 1 or 2 comprises the following steps: S1. Preparation of a perfluoropolyether modified intermediate, the structural formula of which is shown in Formula II: Formula II: S2. The perfluoropolyether modified intermediate and alkoxysilane are added to a solvent and reacted under the action of a catalyst to obtain the perfluoropolyether modified silane compound containing diether bonds.

4. The preparation method according to claim 3, characterized in that: The catalyst is a platinum catalyst, and its dosage is 20~100 ppm of the total mass of the reaction system; The solvent is selected from at least one of 1,3-bis(trifluoromethyl)benzene, hydrofluoroether, and perfluorohexane; The reaction temperature in step S2 is 50~100℃, and the reaction time is 3~8 hours.

5. The preparation method according to claim 4, characterized in that, The platinum catalyst is selected from at least one of Karstedt catalyst, chloroplatinic acid catalyst, and platinum-divinyltetramethyldisiloxane complex.

6. The preparation method according to claim 3, characterized in that, The preparation of the perfluoropolyether modified intermediate in step S1 specifically includes the following sub-steps: S11. Under alkaline conditions, perfluoropolyether alcohol and haloacetic acid ester are mixed and reacted to obtain perfluoropolyether ester compound; S12. The perfluoropolyether ester compound is hydrolyzed and acidified to obtain a perfluoropolyether carboxylic acid compound; S13. The perfluoropolyether carboxylic acid compound is subjected to an addition reaction with an allyl Grignard reagent to obtain the perfluoropolyether modified intermediate.

7. The preparation method according to claim 6, characterized in that: In step S11, the alkali added under alkaline conditions is selected from at least one of sodium hydroxide and potassium hydroxide; the haloacetic ester is selected from at least one of methyl bromoacetate, ethyl bromoacetate, and tert-butyl bromoacetate. In step S12, the hydrolysis is carried out under high temperature reflux conditions; the acid used for acidification is selected from at least one of hydrochloric acid and sulfuric acid; In step S13, the allyl Grignard reagent is allyl magnesium bromide or allyl magnesium chloride, and it is added dropwise. The temperature is controlled at (0±0.5)℃ during the dropwise addition. After the dropwise addition, the temperature is raised to room temperature to continue the reaction. After the reaction, it is quenched with saturated ammonium chloride solution. The preparation method according to claim 6 or 7 is characterized in that: The reaction solvents in steps S11 to S13 are selected from at least one of 1,3-bis(trifluoromethyl)benzene, ethylene glycol dimethyl ether, and perfluorohexane; In step S11, a phase transfer catalyst is also added, wherein the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium bisulfate; the temperature of the mixing reaction is 30~50℃.

8. A surface treatment agent, characterized in that, It contains a perfluoropolyether-modified silane compound with diether bonds as described in claim 1 or 2, and a fluorinated solvent.

9. An application characterized in that, A coating is formed by applying the surface treatment agent as described in claim 9 to the surface of an object.

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