Low valent manganese catalysts and their preparation and use in perfluoropolyether-modified siloxanes

Abstract

The application belongs to the field of organic polymer synthesis and its application, and particularly relates to a low-valence manganese catalyst and its preparation and application in perfluoropolyether modified siloxane. The valence of manganese in the low-valence manganese catalyst is -1, and compared with zero-valence or +1 and +3 valence manganese, the reduction ability is stronger, the catalytic activity is higher, and the catalytic efficiency of the manganese catalyst is further improved. The fingerprint-resistant adhesive prepared by using the perfluoropolyether modified siloxane has excellent characteristics of hydrophobic and oleophobic, high transparency and good friction resistance. The preparation method is simple in operation, simple in process and convenient for industrial production. Meanwhile, the raw materials are cheap and easy to obtain, and the cost is low, so the application is conducive to popularization and application in production practice.

Description

Technical Field

[0001] This invention belongs to the field of organic polymer synthesis and its application, specifically relating to a low-valent manganese catalyst and its preparation and application in perfluoropolyether-modified siloxanes. Background Technology

[0002] With the development of technology, people's demand for smartphones, tablets, cameras, and smart office equipment is increasing. This places higher demands on touchscreens, requiring them not only to maintain the original color and appearance of the product, but also to possess excellent hydrophobic and oleophobic properties, superior light transmittance, a comfortable feel, and resistance to fingerprints, friction, and scratches. To meet these requirements, a coating is needed on the surface of the screen and camera to achieve purposes such as increased screen or camera hardness, friction resistance, waterproofing, moisture resistance, stain and corrosion resistance, and easy cleaning.

[0003] Currently used coating materials mainly include fluorosilicone polymers, silanes, and silicone oils. Organosilicon compounds play an important role in hydrophobic materials; they are often synthesized into nano-SiO2 sols through hydrolysis and polycondensation reactions for hydrophobic treatment of glass surfaces. Organofluorine compounds, with their low surface energy and excellent weather resistance, are also widely used in hydrophobic materials and other fields. However, the long fluorinated chains in fluorosilicone resins are difficult to degrade in the natural environment, and they have drawbacks such as bioaccumulation and high toxicity, which limits their use.

[0004] In recent years, perfluoropolyether materials have been developed that can effectively solve this problem. Perfluoropolyethers not only retain the excellent properties of fluorosilicone resins, such as low surface energy, high heat resistance, and chemical stability, but they are also easily degradable and do not pose a potential hazard to organisms or the environment. Replacing perfluorinated compounds with perfluoropolyethers as novel environmentally friendly hydrophobic and oleophobic coating materials has promising development prospects. However, due to their extremely low glass transition temperature, they remain liquid at room temperature and even low temperatures, making them unsuitable for coating glass surfaces and for use as anti-fingerprint agents alone. They require chemical or polymeric reactions with other compounds (such as siloxanes) to prepare fluorosiloxanes, which are then applied to anti-fingerprint coatings. For example, An et al. prepared highly hydrophobic coating materials by grafting perfluoropolyether-containing acrylates with cage-like siloxanes.

[0005] In 2021, An Qiufeng et al. prepared a type of fluoroether resin by reacting alkoxy-modified fluorinated polysiloxanes with perfluoropolyether alcohols via a dealcoholization reaction. This resin can be used as a coating for touchscreens. For example, patent CN105801797A discloses the reaction of terminal hydroxyl-terminated polysiloxane polymers with isocyanate-containing perfluoropolyethers to prepare fluorinated superhydrophobic self-cleaning and anti-fouling polymers, which are then applied to self-cleaning and anti-fouling coatings. Patent CN101501046A discloses a method for preparing perfluoropolyether silanes, which are then applied to the surface treatment of ceramics and glass, providing hydrophobic, oleophobic, and stain-removing effects. Patent CN102666759A discloses the preparation of perfluoropolyether-containing siloxanes and silazanes, which are then applied to anti-fouling coatings. While these technologies and processes can solve problems related to touchscreens such as stain resistance, fingerprint resistance, and abrasion resistance, these perfluoroether-containing siloxanes all contain Si-C bonds in their structure. Therefore, the synthesis requires functionalization of perfluoropolyethers and siloxanes, followed by dealcoholization, free radical reactions, or hydrosilylation reactions to prepare siloxanes containing perfluoropolyethers. However, the catalysts used in these methods are generally expensive transition metal catalysts, such as platinum. Furthermore, the preparation process is cumbersome and costly, hindering industrial production. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing technologies in the preparation of siloxanes containing perfluoropolyethers, which involve expensive transition metal catalysts, cumbersome processes, high costs, and produce anti-fingerprint adhesives with poor hydrophobicity and oleophobicity, low transparency, and poor abrasion resistance. It provides a low-cost manganese catalyst and its preparation method in perfluoropolyether-modified siloxanes, and applies it to the preparation of anti-fingerprint adhesives, anti-fingerprint coatings, and coating materials.

[0007] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution:

[0008] A low-valent manganese catalyst, characterized in that the structural formula of the low-valent manganese catalyst is shown in Formula 4 below:

[0009]

[0010] The manganese in the low-valence manganese catalyst of the present invention has a valence state of -1, which has a stronger reducing ability and higher catalytic activity compared with zero-valence or +1 or +3 manganese, thus further improving the catalytic efficiency of manganese catalyst.

[0011] A method for preparing a perfluoropolyether-modified siloxane includes the following steps:

[0012] A monohydroxy-terminated perfluoropolyether, a trialkoxysilane, and a low-valent manganese catalyst as described above are added to a solvent-free or fluorine-containing organic solvent, and then heated to carry out a dehydrogenation reaction to obtain a perfluoropolyether-modified siloxane.

[0013] Preferably, the structural formula of the single hydroxyl-terminated perfluoropolyether is any one of the following formulas (1), (2), and (3);

[0014]

[0015] Preferably, the molecular weight of formula (1) is 500-3000 g / mol; the molecular weight of formula (2) is 800-5000 g / mol; and the molecular weight of formula (3) is 1000-6000 g / mol.

[0016] Preferably, the structure of the trimekoxysilane is HSi(OR)3; wherein R is selected from any one of methyl, ethyl, propyl, isopropyl, butyl, and vinyl.

[0017] As a further preferred option, the general reaction formula for preparing perfluoropolyether-modified siloxanes is shown in Formula 5 below:

[0018]

[0019] Preferably, the amount of the low-cost manganese catalyst added is 1 / 1000 to 1 / 100000 of the mass of the monohydroxy-terminated perfluoropolyether.

[0020] When the amount of low-valent manganese catalyst added is less than 1 / 100,000 of the mass of monohydroxyl-terminated perfluoropolyether, the reaction time will be prolonged, and the reaction is prone to incomplete. However, when the amount of low-valent manganese catalyst added is greater than 1 / 1000 of the mass of monohydroxyl-terminated perfluoropolyether, the excessive amount of low-valent manganese catalyst, although not affecting the reaction, easily leads to waste of raw material resources and increases production costs.

[0021] Preferably, the heating reaction temperature is 80–120°C.

[0022] When the reaction temperature is below 80℃, the reaction rate slows down significantly, resulting in reduced production efficiency. When the reaction temperature is above 120℃, the excessively high temperature can cause the low-valent manganese catalyst to decompose slowly, further affecting the catalytic efficiency.

[0023] Preferably, the fluorinated organic solvent is any one or a combination of two of perfluoroalkanes and fluorinated ethers.

[0024] Preferably, the fluorinated organic solvent is any one or a combination of perfluorohexane, perfluorocyclohexane, perfluoroheptane, 1,1,1,2,3,3,3-heptafluoro-2-2(ethoxydifluoromethyl)-propane, 1,1,2,2,3,3,4,4,4-nonafluoro-1-ethoxy-butane, and perfluorocyclic ethers.

[0025] The preparation method of perfluoropolyether modified siloxane as described above is applied in the fields of anti-fingerprint adhesives, anti-fingerprint coatings, and coating materials.

[0026] Therefore, the present invention has the following beneficial effects:

[0027] (1) The manganese in the low-valence manganese catalyst of the present invention is in the valence state of -1. Compared with zero-valence or +1 or +3-valence manganese, it has stronger reducing ability and higher catalytic activity, further improving the catalytic efficiency of manganese catalyst.

[0028] (2) The preparation method of the present invention is simple to operate and streamlined, making it easy for industrial production. At the same time, the raw materials used are inexpensive and readily available, resulting in low cost, which is conducive to its promotion and application in production practice;

[0029] (3) The anti-fingerprint adhesive prepared by the present invention using perfluoropolyether modified siloxane has excellent properties such as hydrophobicity, oleophobicity, high transparency and good abrasion resistance. Attached Figure Description

[0030] Figure 1 This is the 1H NMR spectrum of low-valent manganese catalyst I.

[0031] Figure 2 This is the carbon NMR spectrum of low-valent manganese catalyst I. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0033] Example 1

[0034] A method for preparing a perfluoropolyether-modified siloxane includes the following steps:

[0035] Under argon protection, monohydroxy-terminated perfluoropolyether (RfOH)1 (molecular weight 3000 g / mol, 20 g, structure as shown in formula (1)), trimethoxysilane (2.91 g), and low-valent manganese catalyst I (2.38 × 10⁻⁶ g) were added sequentially to a 250 mL three-necked flask. - 4 (mmol). The reaction was stirred at 80℃ for approximately 5 hours until no more bubbles were observed. After the reaction was complete, excess trimethoxysilane was removed under reduced pressure to obtain perfluoropolyether-modified siloxane A1. The 1H NMR spectrum of the low-valent manganese catalyst I was as follows: 11H NMR (400MHz, d8-THF), 2.49 (4H, S), 0.19 (36H, S) ppm. The 1H NMR spectrum of low-valent manganese catalyst I is as follows: Figure 1 As shown. The carbon NMR spectrum of low-valent manganese catalyst I is as follows: 13 C10 NMR (100MHz, d8-THF), 238.6, 46.4, 38.7, 3.25. The C10 NMR spectrum of low-valent manganese catalyst I is shown below. Figure 2 As shown.

[0036] Example 2

[0037] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0038] The difference between this embodiment and Embodiment 1 is that:

[0039] A method for preparing a perfluoropolyether-modified siloxane, wherein a monohydroxyl-terminated perfluoropolyether (RfOH)2 (molecular weight 2000 g / mol, 15 g, structure as shown in formula (2)) is used to replace a monohydroxyl-terminated perfluoropolyether (RfOH)1 (molecular weight 3000 g / mol, 20 g, structure as shown in formula (1)); and a low-valent manganese catalyst I (3 × 10⁻⁶ m³ / g) is used. -3 Replace low-valent manganese catalyst I (2.38 × 10 mmol) -4 (mmol); the reaction temperature was replaced with 100℃ instead of 80℃. Everything else was the same as in Example 1. Perfluoropolyether modified siloxane A2 was obtained.

[0040] Example 3

[0041] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0042] The difference between this embodiment and Embodiment 1 is that:

[0043] A method for preparing perfluoropolyether-modified siloxane, wherein a monohydroxyl-terminated perfluoropolyether (RfOH)1 (molecular weight 3000 g / mol, 30 g, structure as shown in formula (3)) is replaced with a monohydroxyl-terminated perfluoropolyether (RfOH)3 (molecular weight 4000 g / mol, 20 g, structure as shown in formula (1)); and a reaction temperature of 120 °C is replaced with 80 °C. All other conditions are the same as in Example 1. Perfluoropolyether-modified siloxane A3 is obtained.

[0044] Example 4

[0045] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0046] The difference between this embodiment and Embodiment 1 is that:

[0047] A method for preparing perfluoropolyether-modified siloxane, wherein a low-valent manganese catalyst I (1×10⁻⁶) is used. -3 Replace low-valent manganese catalyst I (2.38 × 10⁻⁶ mol) -4 (mmol). Everything else was the same as in Example 1. Perfluoropolyether modified siloxane A4 was obtained.

[0048] Example 5

[0049] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0050] The difference between this embodiment and Embodiment 1 is that:

[0051] A method for preparing perfluoropolyether-modified siloxane, wherein a low-valent manganese catalyst I (1×10⁻⁶) is used. -6 Replace low-valent manganese catalyst I (2.38 × 10⁻⁶ mol) -4 (mmol). Everything else was the same as in Example 1. Perfluoropolyether modified siloxane A5 was obtained.

[0052] Example 6

[0053] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0054] The difference between this embodiment and Embodiment 1 is that:

[0055] A method for preparing perfluoropolyether-modified siloxane, wherein the reaction temperature is replaced with 100℃ instead of 80℃. Everything else is the same as in Example 1. Perfluoropolyether-modified siloxane A6 is obtained.

[0056] Example 7

[0057] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0058] The difference between this embodiment and Embodiment 1 is that:

[0059] A method for preparing perfluoropolyether-modified siloxane, wherein the reaction temperature is replaced with 120°C instead of 80°C. Everything else is the same as in Example 1. Perfluoropolyether-modified siloxane A7 is obtained.

[0060] Example 8

[0061] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0062] The difference between this embodiment and Embodiment 1 is that:

[0063] A method for preparing perfluoropolyether-modified siloxane, wherein 120 mL of perfluorotetrahydrofuran is added as a fluorinated organic solvent to a 250 mL three-necked flask. All other steps are the same as in Example 1. Perfluoropolyether-modified siloxane A8 is obtained.

[0064] Example 9

[0065] This embodiment provides a method for preparing perfluoropolyether-modified siloxane.

[0066] The difference between this embodiment and Embodiment 1 is that:

[0067] A method for preparing a perfluoropolyether-modified siloxane, wherein triethoxysilane (3.91 g) is used instead of trimethoxysilane (2.91 g). Everything else is the same as in Example 1. Perfluoropolyether-modified siloxane A9 is obtained.

[0068] Comparative Example 1

[0069] This comparative example provides a method for preparing perfluoropolyether-modified siloxane.

[0070] The difference between this comparative example and Example 1 is as follows:

[0071] A method for preparing perfluoropolyether-modified siloxane, wherein the reaction temperature is replaced with 70°C instead of 80°C. Everything else is the same as in Example 1. Perfluoropolyether-modified siloxane A10 is obtained.

[0072] Comparative Example 2

[0073] This comparative example provides a method for preparing perfluoropolyether-modified siloxane.

[0074] The difference between this comparative example and Example 1 is as follows:

[0075] A method for preparing perfluoropolyether-modified siloxane, wherein the reaction temperature is replaced with 130℃ instead of 80℃. Everything else is the same as in Example 1. Perfluoropolyether-modified siloxane A11 is obtained.

[0076] Comparative Example 3

[0077] This comparative example provides a method for preparing perfluoropolyether-modified siloxane.

[0078] The difference between this comparative example and Example 1 is as follows:

[0079] A method for preparing perfluoropolyether-modified siloxane, wherein a low-valent manganese catalyst I (1×10⁻⁶) is used. -4 Replace low-valent manganese catalyst I (2.38 × 10⁻⁶ mol) -4 (mmol). Everything else was the same as in Example 1. Perfluoropolyether modified siloxane A12 was obtained.

[0080] Comparative Example 4

[0081] This comparative example provides a method for preparing perfluoropolyether-modified siloxane.

[0082] The difference between this comparative example and Example 1 is as follows:

[0083] A method for preparing perfluoropolyether-modified siloxane, wherein a low-valent manganese catalyst I (5×10⁻⁶) is used. -4 Replace low-valent manganese catalyst I (2.38 × 10⁻⁶ mol) -4 (mmol). Everything else was the same as in Example 1. Perfluoropolyether modified siloxane A13 was obtained.

[0084] Perfluoropolyether-modified siloxanes A1-A13 were prepared according to the preparation methods in Examples 1-9 and Comparative Examples 1-4, respectively, and their abrasion resistance was tested. The abrasion resistance test results of the perfluoropolyether-modified siloxanes are shown in Table 1 below. The abrasion resistance test method is as follows:

[0085] Steel wool friction conditions: steel wool, 1000g pressure, 20mm*20mm, 40mm stroke, 40cycle / min;

[0086] Rubber friction conditions: Minoan rubber, 40mm stroke, 40 cycles / min, 1000g pressure;

[0087] Product status: Continuous AR+ spray painting machine;

[0088] Spray painting machine parameters: Flow rate: 20mL / min; Conveyor speed: 800mm / min;

[0089] Temperature and humidity: 19.6℃, 39%.

[0090] Film preparation conditions: (1) Prepare a spraying liquid by mixing perfluoropolyether modified siloxane and diluent in a mass ratio of 7:1000; (2) After uniformly spraying the spraying liquid onto the glass plate, place it in an oven at 100℃ for 15 to 25 minutes.

[0091] Blank test group: blank glass slides without any adhesive coating.

[0092] Table 1: Abrasion Resistance Test Results of Perfluoropolyether Modified Siloxane

[0093]

[0094] Analysis of the data in Table 1 shows that the anti-fingerprint adhesive prepared by the present invention using perfluoropolyether modified siloxane has excellent properties such as hydrophobicity, oleophobicity, high transparency, and good abrasion resistance.

[0095] The above description is merely a detailed explanation of preferred embodiments and principles of the present invention. For those skilled in the art, there may be changes in specific implementation methods based on the ideas provided by the present invention, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A low-cost manganese catalyst, characterized in that, The structural formula of the low-cost manganese catalyst is shown in Formula 4 below: Formula 4.

2. A method for preparing a perfluoropolyether-modified siloxane, characterized in that, Includes the following steps: A monohydroxy-terminated perfluoropolyether, a trialkoxysilane, and a low-valent manganese catalyst as described in claim 1 are added to a solvent-free or fluorine-containing organic solvent, and then heated to carry out a dehydrogenation reaction to obtain a perfluoropolyether-modified siloxane.

3. The method for preparing a perfluoropolyether-modified siloxane according to claim 2, characterized in that, The structural formula of the single hydroxyl-terminated perfluoropolyether is any one of the following formulas (1), (2), and (3); 。 4. The method for preparing a perfluoropolyether-modified siloxane according to claim 3, characterized in that, The molecular weight of formula (1) is 500~3000 g / mol; the molecular weight of formula (2) is 800~5000 g / mol; and the molecular weight of formula (3) is 1000~6000 g / mol.

5. The method for preparing a perfluoropolyether-modified siloxane according to claim 2, characterized in that, The structural formula of the trialkoxysilane is HSi(OR)3; wherein R is selected from any one of methyl, ethyl, propyl, isopropyl, butyl, and vinyl.

6. A method for preparing a perfluoropolyether-modified siloxane according to claim 2 or 3, characterized in that, The amount of the low-cost manganese catalyst added is 1 / 1000 to 1 / 100000 of the mass of the monohydroxy-terminated perfluoropolyether.

7. The method for preparing a perfluoropolyether-modified siloxane according to claim 2, characterized in that, The heating reaction temperature is 80~120℃.

8. The method for preparing a perfluoropolyether-modified siloxane according to claim 2, characterized in that, The fluorinated organic solvent is any one or a combination of two of perfluoroalkanes and fluorinated ethers.

9. A method for preparing a perfluoropolyether-modified siloxane according to claim 2 or 8, characterized in that, The fluorinated organic solvent is any one or a combination of perfluorohexane, perfluorocyclohexane, perfluoroheptane, 1,1,1,2,3,3,3-heptafluoro-2-2(ethoxydifluoromethyl)-propane, 1,1,2,2,3,3,4,4,4-nonafluoro-1-ethoxy-butane, and perfluorocyclic ethers.

10. The application of the preparation method of perfluoropolyether modified siloxane as described in any one of claims 2 to 9 in the fields of anti-fingerprint adhesives, anti-fingerprint coatings, and coating materials.

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