Perfluoropolyether siloxane, preparation method thereof and anti-fingerprint agent

Abstract

The invention discloses perfluoropolyether siloxane, a preparation method thereof and an anti-fingerprint agent, and belongs to the field of anti-fingerprint agents. The preparation method comprises the following steps: firstly, preparing a perfluoropolyether intermediate containing an epoxy group, and then reacting with secondary amino siloxane and halogenated alkyl siloxane in sequence to obtain perfluoropolyether siloxane containing a tertiary amine bond. According to the perfluoropolyether siloxane, due to the existence of tertiary amine bonds, the curing temperature can be effectively reduced, and the purpose of curing to form a film at normal temperature is achieved. In addition, after being prepared into an anti-fingerprint agent, the anti-fingerprint agent can act on the surfaces of base materials made of different materials and is cured to form a film, and meanwhile, the anti-fingerprint agent has excellent fingerprint resistance, friction resistance and the like. The preparation method is simple to operate and mild in condition, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the field of anti-fingerprint agents, and specifically relates to a perfluoropolyether siloxane and a preparation method thereof and an anti-fingerprint agent. Background Art

[0002] Conventional anti-fingerprint coatings are generally heat-cured or UV-cured. Heat-cured coatings have better yellowing resistance, but they can only be applied to substrates that can withstand high temperatures. They have good adhesion and good wear resistance on such substrates. They cannot provide good anti-fingerprint effects for materials that are not resistant to high temperatures, such as plastic substrates, and their wear resistance is not high. UV-cured anti-fingerprint coatings have relatively poor yellowing resistance. The surface of substrates such as glass, metal, and ceramics is relatively dense, and the coating cannot penetrate into the interior. In addition, UV-cured anti-fingerprint coatings cannot be bitten, have poor adhesion, cannot improve good wear resistance, and cannot provide long-term anti-fingerprint performance.

[0003] Therefore, there is an urgent need to develop an anti-fingerprint coating that can be cured into a film at room temperature and firmly adheres, and the film layer also has excellent anti-fingerprint and friction resistance properties. Summary of the invention

[0004] In view of the defects of the anti-fingerprint agent in the prior art, such as low friction resistance and inability to cure at room temperature, the first object of the present invention is to provide a perfluoropolyether siloxane, which contains a tertiary amine bond in the molecule, which can effectively reduce the curing temperature and can be cured at room temperature, greatly improving the curing efficiency, avoiding the problems of low adhesion and poor durability caused by the coating with poor yellowing resistance during the thermal curing process, and does not require additional curing equipment, which can effectively reduce the production cost. In addition, the tertiary amine nitrogen in the molecular structure of the perfluoropolyether siloxane connects multiple silicon oxygen bonds to cooperate with the siloxane introduced into the main structure of the perfluoropolyether to greatly improve the adhesion and other properties of the anti-fingerprint agent.

[0005] The second object of the present invention is to provide a method for preparing perfluoropolyether siloxane, which has the advantages of being simple and easy to operate, mild reaction conditions, and fast speed, and is suitable for large-scale production.

[0006] The third object of the present invention is to provide an anti-fingerprint agent, which comprises perfluoropolyether siloxane, and the perfluoropolyether siloxane and other components synergistically give the anti-fingerprint agent good adhesion, good hydrophobicity and wear resistance, and can be cured at room temperature.

[0007] In order to achieve the above object, the present invention provides a perfluoropolyether siloxane having a structural formula as shown in Formula I:

[0008] Formula I;

[0009] Among them, Rf is a perfluoropolyether group, and its structural formula is CF3CF2O (CF3CFCF2O) m (CF2O) n CF2CH2— ; Wherein, m and n are integers ≥ 0, and m and n are not zero at the same time; R1 and R2 are independently selected from , , , In one of the above, R1 and R2 are the same or different.

[0010] R3 is selected from , , , , , , , One of the following, Indicates the bonding site.

[0011] In the molecular structure design of perfluoropolyether siloxane in the technical solution of the present invention, the multiple siloxane groups of R3 connected to the main structure of perfluoropolyether and R1 and R2 connected to the tertiary amine nitrogen can give the anti-fingerprint agent excellent adhesion, and R1, R2 and R3 are triangular in structure, which can form a more stable triangular network structure when acting with the substrate, further improving the adhesion and friction resistance of the anti-fingerprint agent; at the same time, the perfluoropolyether group is far away from the three groups and can be free on the surface of the substrate. This structural design can provide the anti-fingerprint agent with excellent smoothness and hydrophobic antifouling effect. In addition, the two molecules of siloxane and perfluoropolyether main chains are simultaneously connected to nitrogen to form a tertiary amine bond, which can effectively reduce the curing temperature during the curing process, so that the compound can be cured into a film without heating or ultraviolet light irradiation, eliminating the cumbersome curing steps, greatly improving the production efficiency, and effectively reducing the production cost.

[0012] Further preferably, R1 and R2 are ; Experiments have found that when further optimized, the bonding strength and hydrophobic antifouling properties of the anti-fingerprint agent can be improved, and the curing temperature can be significantly reduced.

[0013] More preferably, R3 is ; Experiments have found that further optimization can help further improve the stability, hydrophobicity, antifouling, smoothness and other properties of the anti-fingerprint agent.

[0014] The present invention also provides a method for preparing perfluoropolyether siloxane, which comprises the following steps: in the presence of an alkaline catalyst, subjecting perfluoropolyether alcohol to a substitution reaction I with epichlorohydrin to obtain an intermediate 1; subjecting the intermediate 1 to a ring-opening reaction with a secondary aminosiloxane to obtain an intermediate 2; and subjecting the intermediate 2 to a substitution reaction II with a haloalkylsiloxane to obtain the perfluoropolyether siloxane. Wherein, the perfluoropolyether alcohol has a structural formula as shown in Formula II:

[0015] Formula II; Rf is a perfluoropolyether group, and its structural formula is CF3CF2O (CF3CFCF2O) m (CF2O) n CF2CH2— ; Wherein, m and n are integers ≥ 0, and m and n are not zero at the same time; Intermediate 1 has the structural formula of Formula III:

[0016] Formula III; The secondary aminosiloxane has a structural formula of Formula IV:

[0017] Formula IV; Intermediate 2 has a structural formula of Formula V:

[0018] Formula V; The haloalkylsiloxane has the structural formula VI:

[0019] Formula VI; R1 and R2 are independently selected from , , , In one of the above, R1 and R2 are the same or different.

[0020] R3 is selected from , , , , , , , X is selected from one of F, Cl and Br. More preferably, X is Cl.

[0021] In the synthesis route of the present invention, a substitution reaction is carried out between perfluoropolyether alcohol and epichlorohydrin to graft epoxy groups, and further a reaction is carried out with secondary aminosiloxane and halogenated alkylsiloxane to graft three molecules of siloxane groups, thereby greatly improving the hydrophobic antifouling effect and friction resistance of the coating. In addition, the presence of the tertiary amine bond effectively reduces the curing temperature of the anti-fingerprint agent, and the curing film can be completed without heating or ultraviolet light irradiation, eliminating the cumbersome curing steps, greatly improving the production efficiency, and effectively reducing the production cost.

[0022] As a preferred embodiment, the molar ratio of perfluoropolyether alcohol to epichlorohydrin in the substitution reaction I is 1:(1-1.2); more preferably, the molar ratio of perfluoropolyether alcohol to epichlorohydrin is 1:(1-1.05).

[0023] As a preferred embodiment, the conditions of the substitution reaction I are: temperature of 60-80°C and time of 3-6 hours.

[0024] As a preferred embodiment, the alkaline catalyst is at least one of sodium hydroxide and potassium hydroxide, and the amount added is 1-3 wt % relative to epichlorohydrin. The addition of an appropriate amount of alkaline catalyst promotes the rapid progress of substitution reaction I.

[0025] As a preferred embodiment, the molar ratio of the intermediate 1 to the secondary aminosiloxane is 1:(1-1.2); more preferably, the molar ratio of the intermediate 1 to the secondary aminosiloxane is 1:(1-1.1).

[0026] As a preferred embodiment, the conditions of the ring-opening reaction are: temperature of 30-50° C. and time of 5-6 h.

[0027] As a preferred embodiment, the molar ratio of the intermediate 2 to the haloalkylsiloxane is 1:(1-2.1); more preferably, the molar ratio of the intermediate 2 to the haloalkylsiloxane is 1:(1-1.2).

[0028] As a preferred solution, the conditions of the substitution reaction II are: the temperature is room temperature and the time is 4 to 5 hours.

[0029] As a preferred solution, an appropriate amount of alkaline catalyst may be added to the substitution reaction II to promote the reaction.

[0030] The present invention provides a method for preparing perfluoropolyether siloxane, which specifically comprises the following preparation steps: (1) Weighing perfluoropolyether alcohol and epichlorohydrin and adding them into a reactor, the solvent is tetrahydrofuran, and under the catalysis of sodium hydroxide, the perfluoropolyether alcohol and epichlorohydrin undergo substitution reaction I to obtain intermediate 1; (2) weighing the intermediate 1 and secondary aminosiloxane, adding them into a reactor, using dimethyl sulfoxide as solvent, and refluxing under heating conditions to cause a ring-opening reaction to obtain the intermediate 2; (3) Weigh the intermediate 2 and the haloalkylsiloxane and add them into a reactor. The solvent is tetrahydrofuran. Under the catalysis of sodium hydroxide, the intermediate 2 and the haloalkylsiloxane undergo substitution reaction II to obtain the product.

[0031] Finally, the present invention also provides an anti-fingerprint agent, which contains perfluoropolyether siloxane, and the perfluoropolyether siloxane and other components synergistically give the anti-fingerprint agent good adhesion, good hydrophobicity and wear resistance, and can be cured at room temperature.

[0032] As a preferred solution, the diluent is one of 3M 7100, 3M7200, and 3M7300.

[0033] As a preferred embodiment, the mass ratio of perfluoropolyether siloxane to diluent in the anti-fingerprint agent is (0.1-2): (98-99.9); further preferably, the mass ratio of perfluoropolyether siloxane to diluent is (0.6-2): (99.4-99.9). The amount of perfluoropolyether siloxane used in the anti-fingerprint agent of the present invention is small, which can save reagent costs, and can achieve good curing effect at room temperature, and the curing time can be greatly reduced by increasing the curing temperature.

[0034] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (1) The perfluoropolyether siloxane provided by the present invention can give the anti-fingerprint agent excellent adhesion by grafting three molecules of siloxane groups on the perfluoropolyether, and R1, R2 and R3 are distributed in a triangular shape in structure, which can form a more stable triangular network structure when interacting with the substrate, further improving the adhesion and friction resistance of the anti-fingerprint agent; importantly, the presence of the tertiary amine bond effectively reduces the curing temperature of the anti-fingerprint agent, and the curing film can be completed without heating or ultraviolet light irradiation, eliminating the cumbersome curing steps, greatly improving the production efficiency, and effectively reducing the production cost.

[0035] (2) The method for preparing perfluoropolyether siloxane provided by the present invention has the advantages of simple operation, mild reaction conditions, no need for expensive catalysts, high reaction rate, etc., and is suitable for industrial production.

[0036] (3) The anti-fingerprint agent of the present invention can be cured at room temperature. After being coated on the surface of a glass substrate, it has the advantages of good hydrophobicity, high light transmittance and good wear resistance, and its initial water drop angle is greater than or equal to 115°. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the perfluoropolyether siloxane prepared in Example 1. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be further described below in conjunction with specific embodiments of the present invention. It should be noted that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments; these embodiments are only for a better understanding of the present invention, rather than limiting the scope of protection of the present invention.

[0039] Unless otherwise specified, all reagents and raw materials used in the present invention are commercially available products or products that can be prepared by known methods.

[0040] Example 1

[0041] This embodiment provides a perfluoropolyether siloxane, the structural formula of which is as follows:

[0042] Among them, the structural formula of Rf is CF3CF2O (CF3CFCF2O) 12 (CF2O) 12 CF2CH2— .

[0043] The preparation method comprises the following steps: (1) Weighing a molar ratio of 1:1.05 perfluoropolyether alcohol (structural formula: Rf-CH2OH, wherein the structural formula of Rf is the same as above) and epichlorohydrin are added into a reactor, the solvent is tetrahydrofuran, and under the catalysis of 1.5wt% sodium hydroxide (relative to the amount of epichlorohydrin added), at 70°C, the perfluoropolyether alcohol and epichlorohydrin undergo substitution reaction I (reaction time: 4h) to obtain intermediate 1; (2) Weighing intermediate 1 and bis(triethoxysilylpropyl)amine in a molar ratio of 1:1.1, adding them into a reactor, using dimethyl sulfoxide as solvent, heating under reflux at 40°C, causing a ring-opening reaction (reaction time: 5 h), and obtaining intermediate 2; (3) The intermediate 2 and 3-chloropropyltriethoxysilane in a molar ratio of 1:2 were weighed and added into a reactor (at room temperature). The solvent was tetrahydrofuran. Under the catalysis of 2 wt % sodium hydroxide (relative to the amount of 3-chloropropyltriethoxysilane), the intermediate 2 and 3-chloropropyltriethoxysilane underwent substitution reaction II (reaction time was 4 h), and the product yield was 88%.

[0044] Example 2

[0045] This embodiment provides a perfluoropolyether siloxane, the structural formula of which is as follows:

[0046] Among them, the structural formula of Rf is CF3CF2O (CF3CFCF2O) 12 (CF2O) 12 CF2CH2— .

[0047] The preparation method comprises the following steps: (1) Weighing perfluoropolyether alcohol (structural formula: Rf-CH2OH, wherein the structural formula of Rf is the same as above) and epichlorohydrin in a molar ratio of 1:1.05 and adding them into a reactor, the solvent is tetrahydrofuran, and under the catalysis of 1.7wt% sodium hydroxide (relative to the amount of epichlorohydrin), the perfluoropolyether alcohol and epichlorohydrin undergo substitution reaction I (reaction time: 4h) at 70°C to obtain intermediate 1; (2) Weighing intermediate 1 and bis(trimethoxysilylpropyl)amine in a molar ratio of 1:1.15, adding them into a reactor, using dimethyl sulfoxide as solvent, heating under reflux at 40°C, causing a ring-opening reaction (reaction time: 6 h), and obtaining intermediate 2; (3) Intermediate 2 and 3-chloropropyltrimethoxysilane in a molar ratio of 1:1.1 were weighed and added to a reactor (room temperature). The solvent was tetrahydrofuran. Under the catalysis of 1.7wt% sodium hydroxide (relative to the amount of 3-chloropropyltrimethoxysilane), intermediate 2 and 3-chloropropyltrimethoxysilane underwent substitution reaction II (reaction time was 4h) to obtain the product. The product yield was 85%.

[0048] Example 3

[0049] This embodiment provides a perfluoropolyether siloxane, the structural formula of which is as follows:

[0050] Among them, the structural formula of Rf is CF3CF2O(CF3CFCF2O)5(CF2O)5CF2CH2— .

[0051] The preparation method comprises the following steps: (1) Weighing a molar ratio of 1:1.05 perfluoropolyether alcohol (structural formula: Rf-CH2OH, wherein the structural formula of Rf is the same as above) and epichlorohydrin are added into a reactor, the solvent is tetrahydrofuran, and under the catalysis of 1.5wt% sodium hydroxide (relative to the amount of epichlorohydrin), the perfluoropolyether alcohol and epichlorohydrin undergo substitution reaction I at 80°C (reaction time: 4h) to obtain intermediate 1; (2) Weighing the intermediate 1 and bis(triethoxysilylpropyl)amine in a molar ratio of 1:1.1, adding them into a reactor, using dimethyl sulfoxide as the solvent, heating under reflux at 40°C, causing a ring-opening reaction (reaction time: 6 h), and obtaining the intermediate 2; (3) Intermediate 2 and 3-bromoethyltriethoxysilane in a molar ratio of 1:1.15 were weighed and added to a reactor (room temperature). The solvent was tetrahydrofuran. Under the catalysis of 2wt% sodium hydroxide (relative to the amount of 3-bromoethyltriethoxysilane), intermediate 2 and 3-bromoethyltriethoxysilane underwent substitution reaction II (reaction time was 5h) to obtain the product. The product yield was 87%.

[0052] Example 4 This embodiment provides a perfluoropolyether siloxane, the structural formula of which is as follows:

[0053] Among them, the structural formula of Rf is CF3CF2O (CF3CFCF2O) 10 (CF2O) 10 CF2CH2— .

[0054] The preparation method comprises the following steps: (1) Weighing a molar ratio of 1:1.04 perfluoropolyether alcohol (structural formula: Rf-CH2OH, wherein the structural formula of Rf is the same as above) and epichlorohydrin are added into a reactor, the solvent is tetrahydrofuran, and under the catalysis of 1.6wt% sodium hydroxide (relative to the amount of epichlorohydrin), at 70°C, the perfluoropolyether alcohol and epichlorohydrin undergo substitution reaction I (reaction time: 4h) to obtain intermediate 1; (2) Weigh the intermediate 1 and 3-triethoxysilyl-N-(3-(trimethoxysilyl)propyl)-1-amine in a molar ratio of 1:1.1 and add them to the reactor. The solvent is dimethyl sulfoxide. Reflux under heating conditions of 50°C to cause a ring-opening reaction (reaction time is 5 hours) to obtain intermediate 2; (3) Intermediate 2 and 3-chloroethyltriethoxysilane in a molar ratio of 1:2.1 were weighed and added to a reactor (room temperature). The solvent was tetrahydrofuran. Under the catalysis of 2wt% sodium hydroxide (relative to the amount of 3-chloroethyltriethoxysilane), intermediate 2 and 3-chloroethyltriethoxysilane underwent substitution reaction II (reaction time was 4h) to obtain the product. The product yield was 83%.

[0055] Comparative Example 1 Compared with Example 1, the only difference is that bis(triethoxysilylpropyl)amine is replaced by aminopropyltriethoxysilane, and the other preparation steps are the same.

[0056] Comparative Example 2 Compared with Example 1, the only difference is that 3-chloropropyltriethoxysilane is replaced by 1-chloropropane, and the other preparation steps are the same.

[0057] The perfluoropolyether siloxane prepared in Examples 1, 2, 3 and Comparative Examples 1 and 2 is evenly mixed with the diluent 3M 7200 (mass ratio is 0.6:99.4), and then evenly and precisely applied to the surface of the glass substrate by spraying or spin coating.

[0058] By testing the light transmittance, initial water drop angle, rubber friction resistance, steel wool friction resistance, dynamic friction coefficient and other properties of the substrate surface, the test results are shown in Table 1 below.

[0059]

[0060] Light transmittance test method: Light transmittance is measured by TH-110 light transmittance haze meter. Place the coated substrate on the test platform, press the HOLD key of the instrument, and start the test after the instrument passes the self-calibration, and record the test results.

[0061] Hydrophobic angle test method: The static contact angle of the coating is measured by a JGW-360a contact angle meter. The test liquid volume is 2μL, the test environment is 24±1℃, and the relative humidity is 45±1%. The water droplet touch angle is measured at 5 points and the average value is taken.

[0062] Rubber abrasion resistance test method: The rubber abrasion resistance test is measured by ZJ-339-GSR wear tester. The coated substrate is fixed on the tester, the pressure is set to 1000g, the stroke is set to 40mm, the speed is 40cycles / min, and the test results of the substrate water drop angle are recorded after the test.

[0063] Steel wool abrasion resistance test method: The steel wool abrasion resistance test is measured by ZJ-339-GSR wear tester. The coated substrate is fixed on the tester. The rubber model is MUNBANGSAWOO, the pressure is set to 1000g, the stroke is set to 40mm, the speed is 40cycles / min, 8000 times, and the substrate water drop angle test results are recorded after the end.

[0064] Dynamic friction coefficient (COF) test method: The dynamic friction coefficient of the substrate surface is measured using an MXD-02 friction coefficient tester with a load of 200g.

[0065] As shown in Table 1, it can be seen from the data of Examples 1 to 4 that after being coated on the surface of the glass substrate, the anti-fingerprint agent has the advantages of good hydrophobicity, high light transmittance, good wear resistance and low dynamic friction coefficient, and its initial water drop angle is greater than or equal to 115°. Among them, the perfluoropolyether siloxane prepared by Example 1 has more excellent comprehensive performance. Compared with Example 1, Comparative Example 1 does not have the characteristics of room temperature curing due to the replacement of tertiary amine with primary amine, and the other properties will also decrease; in addition, while Comparative Example 2 has one less siloxane molecule, its hydrophobic antifouling, friction resistance and other properties are significantly reduced.

[0066] The above embodiments are only for better explanation of the principles and practical applications of the present invention, so that those skilled in the relevant technical field can better understand and utilize the present invention, but they are not intended to limit the patent scope of the present invention. All equivalent changes made using the contents of the present invention are within the patent protection scope of the present invention.

Claims

1. A perfluoropolyether siloxane, characterized in that: It has the following structural formula I: ； Formula I; Among them, Rf is a perfluoropolyether group, and its structural formula is CF3CF2O (CF3CFCF2O) m (CF2O) n CF2CH2— ; Wherein, m and n are integers ≥ 0, and m and n are not zero at the same time; R1 and R2 are independently selected from , , , In one of the above, R1 and R2 are the same or different; R3 is selected from , , , , , , , One of; in, Indicates the bonding site.

2. The method for preparing a perfluoropolyether siloxane according to claim 1, characterized in that: Under the action of an alkaline catalyst, a perfluoropolyether alcohol and epichlorohydrin undergo a substitution reaction I to obtain an intermediate 1; the intermediate 1 undergoes a ring-opening reaction with a secondary aminosiloxane to obtain an intermediate 2; the intermediate 2 undergoes a substitution reaction II with a haloalkylsiloxane to obtain a perfluoropolyethersiloxane; Wherein, the perfluoropolyether alcohol has a structural formula as shown in Formula II: ； Formula II; Rf is a perfluoropolyether group, and its structural formula is CF3CF2O (CF3CFCF2O) m (CF2O) n CF2CH2— ; Wherein, m and n are integers ≥ 0, and m and n are not zero at the same time; Intermediate 1 has the structural formula of Formula III: ； Formula III; The secondary aminosiloxane has a structural formula of Formula IV: ； Formula IV; Intermediate 2 has a structural formula of Formula V: ； Formula V; The haloalkylsiloxane has a structure such as Formula VI: ； Formula VI; R1 and R2 are independently selected from , , , In one of the above, R1 and R2 are the same or different; R3 is selected from , , , , , , , One of: X is selected from one of F, Cl, and Br.

3. The method for preparing a perfluoropolyether siloxane according to claim 2, characterized in that: The molar ratio of perfluoropolyether alcohol to epichlorohydrin in the substitution reaction I is 1:(1-1.2).

4. The method for preparing perfluoropolyether siloxane according to claim 3, characterized in that: The conditions of the substitution reaction I are: temperature of 60-80°C and time of 3-6h; The alkaline catalyst is at least one of sodium hydroxide and potassium hydroxide, and the amount added is 1-3 wt % relative to epichlorohydrin.

5. The method for preparing perfluoropolyether siloxane according to claim 2, characterized in that: The molar ratio of the intermediate 1 to the secondary aminosiloxane is 1:(1-1.2).

6. The method for preparing perfluoropolyether siloxane according to claim 5, characterized in that: The conditions of the ring-opening reaction are: temperature of 30-50° C. and time of 5-6 h.

7. The method for preparing perfluoropolyether siloxane according to claim 2, characterized in that: The molar ratio of the intermediate 2 to the haloalkylsiloxane is 1:(1-2.1).

8. The method for preparing perfluoropolyether siloxane according to claim 7, characterized in that: The conditions of the substitution reaction II are: room temperature and 4 to 5 hours.

9. An anti-fingerprint agent, characterized in that: The invention comprises the perfluoropolyether siloxane as claimed in claim 1.

10. The anti-fingerprint agent according to claim 9, characterized in that: The method comprises the following components in parts by weight: 0.1 to 2 parts of the perfluoropolyether siloxane according to claim 1; and 98 to 99.9 parts of a diluent.

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