A perfluoropolyether boric acid compound, surface treatment agent and preparation and application thereof

Abstract

The present invention relates to a perfluoropolyether boric acid compound, a surface treatment agent, and preparation and application thereof. The general chemical structure formula of the perfluoropolyether boric acid compound is as follows: The general chemical structure formula of the surface treatment agent is as follows: The surface treatment agent is used to treat hard surface substrates such as glass and ceramics to make them have anti-fouling and anti-fingerprint properties.

Description

Technical Field

[0001] The invention belongs to the field of new chemical materials, and particularly relates to a perfluoropolyether boric acid compound, a surface treatment agent, and preparation and application thereof. Background Art

[0002] In recent years, the touch panelization of screens has been accelerating, represented by mobile phone displays. However, the glass surface that is often touched is easily contaminated by fingerprints, sweat, cosmetics, etc. Once contaminated, it is difficult to remove and affects its appearance and use. Due to the unique chemical stability, temperature resistance, low friction coefficient and low surface tension of the perfluoropolyether structure, it is widely used in anti-fingerprint coatings on the surface of touch screens. However, the anti-fingerprint agents currently used have the problems of complex preparation routes, high production costs, poor effects, and are mostly monopolized by foreign companies.

[0003] Existing perfluoropolyether siloxane compounds are prone to failure during use. Kyoungmin Min et al. (ACS Appl. Mater. Interfaces 2018, 10, 37498-37506) found through molecular dynamics simulation that when perfluoropolyether siloxane compounds are used as anti-fingerprint agents, the Si-C bonds in their molecular structure are most likely to break under the action of external forces and Si-OHs on the glass surface, thus causing the anti-fingerprint coating to fail.

[0004] Therefore, it is very necessary to develop a perfluoropolyether compound that does not contain Si-C bonds. Summary of the invention

[0005] In view of the problems of the prior art, the technical problem to be solved by the present invention is to provide a perfluoropolyether boric acid compound, a surface treatment agent and a preparation and application thereof, so as to solve the problem in the prior art that Si-C bonds are easily broken during use.

[0006] A perfluoropolyether boric acid compound of the present invention has the following structural formula:

[0007]

[0008] Wherein PFPE is a perfluoropolyether chain, X is a connecting group, Y is an aromatic ring or an alkylene group, x is a positive integer of 1 to 2, and y is a positive integer of 1 to 5.

[0009] Preferably, x is 1, and y is 1-3.

[0010] The perfluoropolyether chain is one of Z-type, K-type, Y-type and D-type, and has a molecular weight of 500 to 12000, preferably 2000 to 8000, and more preferably 4000 to 5000.

[0011] Preferably, X is a connecting group, and the connecting group is one or more of amide, ester, ether, and amine groups.

[0012] Y is an aromatic ring or an alkylene group, more preferably, an aromatic ring.

[0013] Preferably, the structural formula is specifically selected from (including but not limited to) the following structures:

[0014]

[0015] Preparation method of perfluoropolyether boric acid compound:

[0016] The compound of formula (I) having the structure of benzene-boronic acid can be synthesized by standard techniques, for example as shown in the following scheme: Commercially available or easily synthesized chemical formula At least one of the compounds is synthesized by a compound of perfluoropolyether acyl fluoride / acyl chloride with a chemical formula of PFPECOF or PFPECOCl through a common chemical technique such as amidation or esterification. Similar to phenyldiboric acid or phenyltriboric acid.

[0017] Alternatively, a commercially available or easily synthesized chemical formula may be used. The compound of at least one of the above is etherified with a perfluoropolyether alcohol compound having a chemical formula of PFPECH2OH.

[0018] Commercially available or easily synthesized chemical formulas can also be used. The compound is obtained by condensation reduction with a perfluoropolyetheramine having the chemical formula PFPECH2NH2. Similar to phenylenediboronic acid or phenyltriboronic acid.

[0019] The present invention provides a surface treatment agent based on the perfluoropolyether boric acid compound.

[0020] A surface treatment agent of the present invention comprises the following structural compound:

[0021] Wherein PFPE is a perfluoropolyether chain, X is a connecting group, Y is an aromatic ring or an alkylene group, Z is an alkoxy group or a chlorine atom, x is a positive integer of 1 to 2, and y is a positive integer of 1 to 5. Preferably, x is 1, and y is 1 to 3.

[0022] The perfluoropolyether chain is one of Z type, K type, Y type and D type, and has a molecular weight of 500 to 12000, preferably 2000 to 8000, and more preferably 4000 to 5000;

[0023] The connecting group is one or more of amide, ester, ether and amine groups.

[0024] The alkoxy group is a methoxy group or an ethoxy group.

[0025] Preferably, the structural formula of the surface treatment agent is specifically selected from (including but not limited to) the following structures:

[0026]

[0027]

[0028]

[0029]

[0030] A preparation method of the surface treatment agent of the present invention comprises: mixing, reacting and post-treating the perfluoropolyether boric acid compound, a solvent, a catalyst and a connector to obtain the surface treatment agent.

[0031] Furthermore, the preparation method comprises: dissolving the perfluoropolyether boric acid compound in a solvent, adding a catalyst under an ice bath to obtain a solution A; then, under the protection of an inert gas, mixing a connector and a solvent, and dropwise adding the mixture into the solution A under an ice bath, reacting at room temperature for 1 to 2 hours after the dropwise addition is completed, and filtering under the protection of an inert gas to obtain a surface treatment agent.

[0032] The linking agent is one or more of chlorosilane and alkoxysilane, more preferably, tetrachlorosilane, trimethoxychlorosilane or triethoxychlorosilane.

[0033] The catalyst is one or more of an organic acid, an inorganic acid, an organic base, and an inorganic base, preferably an organic acid or an organic base, preferably an organic base, such as (including but not limited to): triethylamine and the like.

[0034] The solvent is one or more of alkanes, alcohols, ethers, ketones, esters, halogenated hydrocarbons, aromatic solvents, fluorinated hydrocarbons, and hydrofluoroethers, and more preferably, a solvent that can simultaneously dissolve the perfluoropolyether boric acid compound, the linker, and the catalyst, specifically including but not limited to: HFE7200, 1,3-ditrifluoromethylbenzene, F113, etc.;

[0035] The ratio of the perfluoropolyether boric acid compound, the catalyst and the linker is: n (boric acid equivalent): n (linker): n: catalyst = 1:1-5:2-10, more preferably: 1:2-3:5-10.

[0036] The anti-fingerprint agent of the present invention contains the surface treatment agent.

[0037] Furthermore, the method for preparing the anti-fingerprint agent comprises: diluting the solution containing the surface treatment agent obtained after filtration with a hydrofluoroether solvent to a certain content, preferably 1 to 10‰, more preferably 3 to 5‰, under the protection of an inert gas.

[0038] The present invention also provides an anti-fingerprint coating using the surface treatment agent.

[0039] First, the surface of the substrate is treated with corona, plasma, etc. to remove pollutants on the surface of the substrate and increase the surface polarity. Then, the anti-fingerprint agent is transferred to the surface of the substrate by common methods such as roller coating, dip coating, spray coating, and evaporation, and then treated at high temperature to form a coating containing a perfluoropolyether compound on the surface of the substrate. The coating has anti-fouling and anti-fingerprint properties.

[0040] In the present invention, the bond energy of the BC bond is higher than that of the Si-C bond, and the B atom is directly connected to the electron-rich group such as the benzene ring, which is more stable. The BO-Si bond formed by B-OH and Si-OH is also relatively stable, and has a higher heat resistance than the Si-O-Si bond. Therefore, if perfluoropolyether boric acid compounds are used to prepare anti-fingerprint agents, since the PFPE chain is connected to the substrate surface through the BC bond BO-Si bond, the problem of the Si-C bond being easily broken during use in the prior art is avoided.

[0041] Beneficial Effects

[0042] The present invention can obtain an anti-fingerprint agent containing BC bonds, which is applied to ceramic or glass surfaces to provide an anti-fingerprint coating with an initial water drop contact angle of more than 110° and a wear resistance of more than 5000 times, thereby solving the problem that the Si-C bonds of current perfluoropolyether siloxane anti-fingerprint agents are easily broken and fail during practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The NMR spectrum of the intermediate product of Example 1;

[0044] Figure 2 This is the NMR spectrum of the perfluoropolyether boronic acid compound of Example 1. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0046] For better comparison, the perfluoropolyethers involved in the examples are all K-type monofunctional perfluoropolyether compounds with a molecular weight of 4500, which are from the Shanghai Institute of Organic Chemistry; all phenylboronic acids are 4-substituted phenylboronic acid, and other reagents are commercially available or homemade.

[0047] Example 1

[0048] a. Synthesis of perfluoropolyether phenylboric acid:

[0049] Under nitrogen protection, add 5.5g of 4-aminophenylboronic acid pinacol ester, 3g of triethylamine, and 20ml of tetrahydrofuran to the reaction bottle. After dissolving and clarifying, add a solution consisting of 90g of PFPECOF and 300ml of perfluorooctane dropwise under ice bath. After the addition is complete, warm to room temperature and react for 10 hours. Filter, add 100ml of methanol twice to the filtrate for washing, and concentrate the fluorine phase to obtain a light yellow oily liquid intermediate. See the attached NMR spectrum Figure 1 .

[0050] Add 18.8 g of the intermediate product from the previous step, 20 ml of trifluoroacetic acid, and 0.72 g of methylboric acid to the reaction flask and stir at room temperature for 12 hours. Remove the low-boiling components under vacuum at a temperature not exceeding 40°C. Dissolve the residue in 100 ml of perfluorooctane, wash with 20 ml of methanol twice, and concentrate the fluorine phase at low temperature to obtain the target product with the following structure (see the attached NMR spectrum): Figure 2 ):

[0051]

[0052] b. Preparation of surface treatment agent

[0053] Dissolve 4.6 g of the perfluoropolyether phenylboric acid synthesized in the previous step in 25 ml HFE7200, add 0.5 g triethylamine under ice bath to prepare solution A. Add 0.34 g silicon tetrachloride and 5 ml HFE7200 to another reaction bottle under nitrogen protection, add solution A dropwise thereto under ice bath. After the addition is complete, react at room temperature for 2 h, filter under inert gas protection, and obtain a surface treatment agent with the following structure, which is directly diluted and used without treatment.

[0054]

[0055] Example 2

[0056] a. Synthesis of perfluoropolyether phenylboric acid:

[0057] Under nitrogen protection, add 0.36 g of sodium hydride and 25 ml of anhydrous tetrahydrofuran to the reaction bottle. Under ice bath and stirring, add a solution consisting of 45 g of perfluoropolyether alcohol PFPECH2OH and 50 ml of HFE7200. After the addition is complete, react at room temperature for 3 hours. Then add a solution consisting of 4.5 g of 4-bromomethylphenylboronic acid pinacol ester and 25 ml of anhydrous tetrahydrofuran at room temperature. After the addition is complete, heat to reflux and react for 12 hours. Add 5 ml of methanol to quench the reaction, filter to remove insolubles, concentrate the filtrate, add 200 ml of perfluorooctane to dissolve, wash with 50 ml × 2 times of methanol, and concentrate the fluorine phase to obtain a colorless oily liquid intermediate.

[0058] Add 18.8 g of the intermediate product from the previous step, 20 ml of trifluoroacetic acid, and 0.72 g of methylboric acid to the reaction flask and stir at room temperature for 12 hours. Remove the low-boiling components under vacuum at a temperature not exceeding 40°C. Add 100 ml of perfluorooctane to the residue to dissolve it, wash it with 20 ml of methanol twice, and concentrate the fluorine phase at low temperature to obtain the target product with the following structure:

[0059]

[0060] b. Preparation of surface treatment agent

[0061] 4.6 g of the perfluoropolyether phenylboric acid synthesized in the previous step was dissolved in 25 ml HFE7200 under ice bath, and 0.5 g of triethylamine was added to prepare solution A. Under nitrogen protection, 0.32 g of trimethoxysilyl chloride and 5 ml HFE7200 were added to another reaction bottle, and solution A was added dropwise under ice bath. After the addition was completed, the reaction was carried out at room temperature for 2 hours, and then filtered under nitrogen protection to obtain a surface treatment agent with the following structure, which was directly diluted and used without treatment.

[0062]

[0063] Example 3

[0064] a. Synthesis of perfluoropolyether phenylboric acid:

[0065] Under nitrogen protection, 45 g of perfluoropolyetheramine PFPECH2NH2, 1.5 g of 4-formylphenylboric acid and 100 ml of hexafluoroisopropanol were added to the reaction bottle and reacted at room temperature for 3 days. Then, 2 g of sodium borohydride was added in batches under ice bath. After the addition was completed, the temperature was slowly raised to room temperature and the reaction was continued for 2 days under stirring.

[0066] Then, the residue was concentrated, 200 ml of perfluorooctane was added to dissolve, and the insoluble matter was removed by filtration. The filtrate was washed with 50 ml of methanol twice, and the fluorine phase was concentrated at low temperature to obtain a light yellow oily liquid perfluoropolyether boronic acid product, the structure of which is as follows:

[0067]

[0068] b. Preparation of surface treatment agent

[0069] 4.6 g of the perfluoropolyether phenylboric acid synthesized in the previous step was dissolved in 25 ml HFE7200 under ice bath, and 0.5 g of triethylamine was added to prepare solution A. Under nitrogen protection, 0.32 g of triethoxychlorosilane and 5 ml HFE7200 were added to another reaction bottle, and solution A was added dropwise under ice bath. After the addition was completed, the reaction was carried out at room temperature for 2 hours, and then filtered under nitrogen protection to obtain a surface treatment agent with the following structure, which was directly diluted and used without treatment.

[0070]

[0071] Comparative Example 1

[0072] A certain brand of anti-fingerprint agent product on the market (structure as follows, PFPE is K type, molecular weight unknown) was directly prepared and used.

[0073]

[0074] Application and performance

[0075] The perfluoropolyether siloxane compound in the above embodiment is diluted with 3M's hydrofluoroether 7200 to prepare a dilution with a mass concentration of 0.5%, which is an anti-fingerprint agent; the high-aluminum silicate glass sheet is pre-treated with piranha lotion, washed with water, and dried with nitrogen for standby use; the pre-treated high-aluminum silicate glass sheet is immersed in the above anti-fingerprint agent, taken out after immersion for 30 minutes, and dried in an oven at 150° C. for 1 hour to form an anti-fingerprint cured film.

[0076] The glass sheet with the anti-fingerprint cured film formed thereon was directly subjected to the following performance tests, and the test results are shown in the table below.

[0077] (1) Contact angle test

[0078] The static contact angle of water was measured using a contact angle tester. The measurement was carried out at room temperature, and the glass sample to be tested was laid flat on the horizontal platform of the contact angle tester and fixed, with a drop size of 5 μl.

[0079] (2) Durability test and analysis of the results of the static initial angle with water

[0080] First, when the surface treatment layer is formed and there is no contact (i.e. the number of frictions is zero), the angle measured is the initial angle. Then the steel wool friction durability evaluation is carried out. Specifically, 0000# steel wool (size 5mmx5mmx2mm) is used to contact the surface treatment layer, a load of 1kg is applied thereon, and then the steel wool is reciprocated 10,000 times at a speed of 60 times / minute under this load-applied contact state, and the static contact angle of water on the contact surface is measured as the evaluation.

[0081] Table 1 Anti-fingerprint agent wear resistance test results

[0082] Example Initial contact angle Contact angle after 10,000 frictions Example 1 117 105 Example 2 118 109 Example 3 117 107 Comparative Example 112 72

[0083] It can be seen from the test results of Examples 1-3 and the comparative example that after the anti-fingerprint agent prepared by the present invention is sprayed on a glass sheet, its static contact angle of water is greater than the contact angle of the anti-fingerprint agent of the control compound. At the same time, the contact angle test results measured after wiping the horizontal coating sample with steel wool show that the anti-fingerprint coating prepared by the perfluoropolyether boric acid compound prepared by the present invention has better wear resistance than the comparative example. This shows that the anti-fingerprint agent prepared by the present invention has excellent comprehensive performance and meets the original intention of the present invention.

Claims

1. A perfluoropolyether boric acid compound, the structural formula of which is as follows: Wherein PFPE is a perfluoropolyether chain, X is a connecting group, Y is an aromatic ring, x is a positive integer of 1 to 2, and y is a positive integer of 1 to 5.

2. The perfluoropolyether boric acid compound according to claim 1, characterized in that: The perfluoropolyether chain is one of Z type, K type, Y type and D type, and has a molecular weight of 500 to 12000; the connecting group is one or more of amide, ester, ether and amine groups.

3. The perfluoropolyether boric acid compound according to claim 1, characterized in that: The structural formula is specifically selected from the following structures:

4. A surface treatment agent based on the perfluoropolyether boric acid compound according to claim 1, characterized in that: The surface treatment agent includes the following structural compounds: Wherein PFPE is a perfluoropolyether chain, X is a connecting group, Y is an aromatic ring, Z is an alkoxy group or a chlorine atom, x is a positive integer of 1 to 2, and y is a positive integer of 1 to 5.

5. The surface treatment agent according to claim 4, characterized in that: The perfluoropolyether chain is one of Z type, K type, Y type and D type, and has a molecular weight of 500 to 12000; the connecting group is one or more of amide, ester, ether and amine groups; and the alkoxy group is methoxy or ethoxy.

6. The surface treatment agent according to claim 4, characterized in that: The compound is specifically selected from the following structures:

7. A method for preparing the surface treatment agent according to claim 4, comprising: The perfluoropolyether boric acid compound according to claim 1, a solvent, a catalyst and a linking agent are mixed, reacted and treated to obtain a surface treating agent.

8. The preparation method according to claim 7, characterized in that: The solvent is one or more of alkanes, alcohols, ethers, ketones, esters, halogenated hydrocarbons, aromatic solvents, and hydrofluoroethers; the catalyst is one or more of organic acids, inorganic acids, organic bases, and inorganic bases; the linker is one or more of chlorosilanes and alkoxysilanes; and the reaction is carried out at room temperature for 1-2 hours.

9. An anti-fingerprint agent, characterized in that: The anti-fingerprint agent contains the surface treatment agent according to claim 4.

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