In-chain functionalized perfluoropolyether and preparation method thereof

Abstract

The invention provides in-chain functionalized perfluoropolyether and a preparation method thereof. The preparation method comprises the following steps: S1, mixing dihydroxy-terminated perfluoropolyether and an oxidation reagent, reacting at 60-120 DEG C for 1-72 hours to obtain an oxidation product, and mixing the oxidation product with alcohol to obtain a first intermediate product; s2, mixing an acetyl compound, a hydrogen pulling reagent and an ether solvent, and reacting to obtain a second intermediate product containing carbon anions; and S3, mixing the first intermediate product and the second intermediate product, carrying out a reaction, and separating the product to obtain the chain-functionalized perfluoropolyether. The elastomer prepared from the in-chain functionalized perfluoropolyether provided by the invention has good low-temperature rebound resilience.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer chemistry, and in particular relates to a chain-functionalized perfluoropolyether and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of smart devices, smart wearables, AI operations, AI homes, and smart express delivery sorting, the demand for high-end AI chips has increased. Chip manufacturing (etching, printing, editing) equipment requires sealing materials with high solvent resistance and high corrosion resistance, and this material is mainly perfluoroether rubber (FFKM). Due to the glass transition temperature (T g ) is around -30℃. Under low temperature conditions, the resilience is poor and the price is high, which has always restricted its application in many fields. Therefore, it is necessary to add T g A polymer with a temperature value of less than -30°C and good compatibility with FFKM can be used to improve the low-temperature performance of FFKM.

[0003] In the existing technology, there is no clear solution to improve the low temperature performance of FFKM. Recently, the research on fluoroelastomers with excellent low temperature performance, perfluoropolyether (PFPE)-based elastomers, has become a hot topic. Obviously, the use of low T g PFPE with a low-temperature value (-110℃~-50℃) can effectively improve the low-temperature performance of FFKM, and PFPE and FFKM are highly compatible and can be mixed and processed in any proportion.

[0004] European patent application EP 0195946A2 discloses a method for preparing a bromine-terminated PFPE, and mentions that the bromine-terminated PFPE can be co-vulcanized with fluororubber under the action of peroxide. The modified fluororubber becomes easier to process, the demoulding property and thermal stability of the product are improved, and its mechanical properties, compression deformation and solvent resistance are almost unchanged. However, bromine-terminated PFPE can only be prepared in the process of producing raw materials, and due to the explosive characteristics of peroxide groups, the safety factor of the preparation is low, which is not suitable for industrialization. Summary of the invention

[0005] In order to solve the above problems in the prior art, the purpose of the present invention is to provide a chain-functionalized perfluoropolyether and a preparation method thereof. The elastomer provided by the present invention has good low-temperature resilience.

[0006] In order to achieve the above object, according to a first aspect of the present invention, a method for preparing a chain-functionalized perfluoropolyether is provided, which comprises: S1, mixing a double-terminated hydroxyl perfluoropolyether, an oxidizing agent, and a solvent to obtain an oxidation product, and mixing the oxidation product with an alcohol to obtain a first intermediate product; S2, mixing an acetyl compound, a hydrogen extraction reagent, and an ether solvent to react to obtain a second intermediate product containing a carbon anion; S3, mixing the first intermediate product and the second intermediate product, reacting them, and separating the products to obtain the in-chain functionalized perfluoropolyether.

[0007] The present invention proposes for the first time the above-mentioned route for preparing chain-functionalized perfluoropolyether. By reacting a first intermediate product (perfluoropolyether ester) and a second intermediate product containing carbon anions, a chain-functionalized perfluoropolyether material with more cross-linking sites is prepared. The elastomer obtained after cross-linking has excellent performance at low temperatures.

[0008] In some preferred embodiments of the present invention, S1 includes a process for post-treating the first intermediate product, and S3 includes a process for post-treating the obtained functionalized perfluoropolyether, and the above post-treatments include filtration, washing, reduced pressure distillation, etc. The specific method can be easily designed by those skilled in the art, and the present invention is not further limited here.

[0009] In some preferred embodiments of the present invention, the solvent in S1 includes water.

[0010] In some preferred embodiments of the present invention, in S1, the reaction temperature is 60-120° C. and the reaction time is 1-72 h.

[0011] In some preferred embodiments of the present invention, in S2, the reaction temperature is 0-60° C. and the reaction time is 0.2-5 h.

[0012] In some preferred embodiments of the present invention, in S3, the reaction temperature is 25-120° C. and the reaction time is 0.5-36 h.

[0013] In some preferred embodiments of the present invention, the average molecular weight of the dihydroxy-terminated perfluoropolyether is 1000-10000.

[0014] In some preferred embodiments of the present invention, the alcohol includes methanol and / or ethanol.

[0015] In some preferred embodiments of the present invention, the dihydroxyl-terminated perfluoropolyether includes one or a combination of two or more of dihydroxyl-terminated K-type perfluoropolyether, dihydroxyl-terminated Y-type perfluoropolyether and dihydroxyl-terminated Z-type perfluoropolyether.

[0016] In some preferred embodiments of the present invention, the acetyl compound includes one or a combination of two or more of halogenated ethyl acetate, halogenated methyl acetate, ethyl acetate, methyl acetate, halogenated acetone, acetone, halogenated ethyl malonate, halogenated methyl malonate, ethyl malonate, and methyl malonate.

[0017] In some preferred embodiments of the present invention, the oxidizing agent includes one or a combination of two or more of potassium permanganate, potassium dichromate, sodium dichromate, chromium trioxide, potassium peroxymonosulfonate, nitric acid, oxygen, hydrogen peroxide, dimethyl sulfoxide-dicyclohexylcarbodiimide complex, and sodium perchlorate.

[0018] In some preferred embodiments of the present invention, the hydrogen extraction reagent includes one or a combination of two or more of sodium methoxide, sodium ethoxide, sodium isopropoxide, potassium tert-butoxide, sodium hydride, potassium hydride, lithium diisopropylamide, n-butyl lithium, and sec-butyl lithium.

[0019] In some preferred embodiments of the present invention, the ether solvent includes one or a combination of two or more of tetrahydrofuran, dioxane, methyl tert-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether.

[0020] In some preferred embodiments of the present invention, the molar ratio of the double-terminated hydroxyl perfluoropolyether to the oxidizing agent is 1:1-10; preferably, the molar ratio of the acetyl compound to the hydrogen extraction agent is 1:0.9-3.

[0021] According to another aspect of the present invention, a chain-functionalized perfluoropolyether prepared according to the above-mentioned preparation method is provided. The structural formula of the chain-functionalized perfluoropolyether is presumed to be -(R f -A) n -R f -, where R f It is a perfluoropolyether, and A contains an acetyl group.

[0022] According to another aspect of the present invention, there is provided a perfluoropolyether-based elastomer obtained by cross-linking the above-mentioned chain-functionalized perfluoropolyether.

[0023] In some preferred embodiments of the present invention, the chain-functionalized perfluoropolyether prepared by the present invention is vulcanized and cross-linked to obtain the perfluoropolyether-based elastomer. The specific cross-linking method is well known to those skilled in the art and is not further limited here.

[0024] Compared with the prior art, the chain-functionalized perfluoropolyether prepared by the present invention can significantly improve the low-temperature performance of perfluoroether rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The infrared spectrum of the double-terminal Z-type perfluoropolyether methyl ester in Example 1 is shown.

[0026] Figure 2 The infrared spectrum of the bromine-containing perfluoropolyether in Example 1 is shown.

[0027] Figure 3 The infrared spectrum of the Z-type perfluoropolyether carboxylic acid in Example 2 is shown.

[0028] Figure 4 The H-NMR spectrum of the polyester Z-type perfluoropolyether in Example 5 is shown.

[0029] Figure 5 The infrared spectrum of the chain-terminated allyl Z-type perfluoropolyether in Example 5 is shown. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0031] The sources of some reagents used in the following examples and comparative examples are as follows: Double-terminated hydroxyl Z-type perfluoropolyether (Fluorolink D10H, abbreviated as D10H), double-terminated Y-type perfluoropolyether methyl ester: industrial grade, purchased from Solvay, Italy. Double-terminated K-type perfluoropolyether methyl ester: industrial grade, purchased from Tianjin Changlu Chemical New Materials Co., Ltd. Potassium permanganate, nitric acid, hydrogen peroxide, methanol: reagent grade, Sinopharm Chemical Reagent Co., Ltd. Sodium methoxide, sodium isopropoxide, ethyl fluoroacetate, bromotrifluoroacetone, tetrahydrofuran, methyl tert-butyl ether: reagent grade, Shanghai Titan Technology Co., Ltd.

[0032] Analysis and evaluation methods: The polymer was scanned by nuclear magnetic resonance (NMR) using a Bruker MX-400 NMR spectrometer produced by Bruker, Germany: 10-15 mg of the product was dissolved in a NMR tube, deuterated chloroform was used as the solvent, and the scanning frequency was 400 MHz.

[0033] Fourier transform infrared spectrometer (FTIR): Model: Bruker Tensor 27. The infrared spectrum of the product was measured by attenuated total reflectance (ATR). The test conditions were: resolution 3 cm -1 , scanning range 4000-500cm -1 . Sample preparation: film coating method and tablet pressing method; reference substance: potassium bromide.

[0034] Example 1

[0035] This embodiment provides a method for preparing a chain-functionalized perfluoropolyether, which specifically comprises: S1, 100 g D10H (average molecular weight of about 1500, molecular weight is average molecular weight unless otherwise specified) and 50.4 g nitric acid aqueous solution (nitric acid mass fraction of 50%) were placed in a three-necked flask, heated to 45 °C, stirred for 30 min, then 105 g potassium permanganate was added in batches (5 times), stirred for 1 h, heated to 95 °C, stirred for 24 h, then cooled to 40 °C, 100 g methanol was added in sequence and rapidly stirred for 30 min, then filtered, the filter cake was washed with fluorocarbon solvent for 3 times, and finally the filtrate was separated and concentrated to obtain 95 g double-terminal Z-type perfluoropolyether methyl ester (first intermediate product), the infrared spectrum of which is shown as follows: Figure 1 As shown, 3305 cm -1 The hydroxyl peak disappeared, 1796 cm -1 The carbon-oxygen double bond peak on the ester group appears.

[0036] S2, add 3.18 g of bromotrifluoroacetone, 20 mL of methyl tert-butyl ether, 1.9 g of sodium methoxide and 3 mL of methanol into a three-necked flask, heat to 60 °C, and stir for 2 h to obtain an intermediate product containing a carbon anion.

[0037] S3, add 50 g of double-terminal Z-type perfluoropolyether methyl ester to the intermediate product containing carbon anions, continue stirring at 60°C for 12 h, then cool to room temperature, add 10 mL of 1 mol / L hydrochloric acid and 50 mL of fluorocarbon solvent, stir for 10 min, then separate and concentrate to obtain 45 g of light yellow bromine-containing perfluoropolyether, whose infrared spectrum is shown in Figure 2 As shown, 1704 cm -1 The carbon-oxygen double bond peak on the keto group appears at 3469 cm -1 The structural formula of the bound water peak on the keto group is speculated as follows: .

[0038] Example 2 This embodiment provides a method for preparing a chain-functionalized perfluoropolyether, which specifically comprises: S1, 100 g D10H (molecular weight about 1500) and 100 g distilled water were placed in a three-necked flask, heated to 45 °C, stirred for 30 min, then 105 g (total) potassium permanganate was added in batches (5 times), stirred for 1 h, heated to 95 °C, stirred for 7 h, cooled to 40 °C, and slowly added with hydrogen peroxide (mass fraction 10%) aqueous solution until the solid disappeared, then stirred at 60 °C for 6 h, cooled to room temperature, separated, and the lower liquid was concentrated to obtain 90 g Z-type perfluoropolyether carboxylic acid, whose infrared spectrum is shown as follows: Figure 3 As shown, 1782 cm -1The carbon-oxygen double bond peak on the carboxylic acid appears, and the pH value is 1~2; 20 g of methanol is added to 90 g of Z-type perfluoropolyether carboxylic acid, stirred at 50°C for 5 h, cooled, separated and concentrated to obtain 88 g of colorless and transparent double-terminal Z-type perfluoropolyether methyl ester (the first intermediate product).

[0039] S2, add 3.18 g of bromotrifluoroacetone, 20 mL of tetrahydrofuran, 2.9 g of sodium isopropoxide and 3 mL of methanol into a three-necked flask, heat to 60 °C, and stir for 2 h to obtain an intermediate product containing a carbon anion.

[0040] S3, add 50 g of double-terminal Z-type perfluoropolyether methyl ester to the intermediate product containing carbon anions, continue stirring for 12 h, cool to room temperature, add 10 mL of 1 mol / L hydrochloric acid and 50 mL of fluorocarbon solvent, stir for 10 min, then separate and concentrate to obtain 48 g of light yellow bromine-containing perfluoropolyether, the structural formula of which is speculated as follows: .

[0041] Example 3 The difference from Example 2 is that the double-terminal Z-type perfluoropolyether methyl ester is replaced by the double-terminal K-type perfluoropolyether methyl ester, and the rest remains unchanged to obtain the chain-brominated K-type perfluoropolyether methyl ester, the structural formula of which is estimated as follows, and the yield is about 85%: .

[0042] Example 4 The difference from Example 2 is that the Z-type perfluoropolyether methyl ester is replaced by the double-terminal Y-type perfluoropolyether methyl ester, and the rest remains unchanged to obtain the chain-brominated Y-type perfluoropolyether methyl ester, the structural formula of which is estimated as follows, and the yield is about 80%: .

[0043] Example 5 The difference from Example 2 is that bromotrifluoroacetone is replaced by ethyl fluoroacetate, and the rest remains unchanged to obtain polyester Z-type perfluoropolyether with a yield of about 95%. Its structural formula is estimated as follows, and its H NMR spectrum is as follows Figure 4 As shown, 2.75~3.34 ppm is the H peak on the methyl ester, and 3.63~3.99 ppm is the CH peak in the ethyl group in the chain. 2 The H peak on the left is 0.67-0.91 ppm, which is the CH 3 H peak on: ; Then, 20 g of polyester Z-type perfluoropolyether, 1.7 g of allylamine and 10 mL of methyl tert-butyl ether were reacted in a three-necked flask at 50°C for 24 h, and then the by-products and excess allylamine were removed under reduced pressure at 60°C to obtain a mid-chain end allyl Z-type perfluoropolyether with a yield of about 90%. Its structural formula is speculated as shown below, and its infrared spectrum is shown in Figure 5 As shown: .

[0044] Example 6 The difference from Example 5 is that the double-terminal Z-type perfluoropolyether methyl ester is replaced by the double-terminal K-type perfluoropolyether methyl ester, and the rest remains unchanged, to obtain the mid-chain end allyl K-type perfluoropolyether methyl ester, with a yield of about 95%.

[0045] Example 7 The difference from Example 5 is that the double-terminal Z-type perfluoropolyether methyl ester is replaced by a double-terminal Y-type perfluoropolyether methyl ester, and the rest remains unchanged, to obtain a mid-chain terminal allyl Y-type perfluoropolyether methyl ester with a yield of about 90%.

[0046] Preparation of perfluoropolyether-based elastomers: The chain-functionalized perfluoropolyether in Examples 2 to 7 was mixed with perfluoroether rubber (grade 31TZ, 3M, USA) at a mass ratio of 20:80, and then peroxide DCP (added amount accounted for 2% of the mass of perfluoroether rubber) and crosslinking agent TAIC (added amount accounted for 1% of the mass of perfluoroether rubber) were added and mixed for multiple times. After curing at 200°C for 4 hours, perfluoropolyether-based elastomers were prepared, which were named samples A to F in turn, and their glass transition temperatures are shown in Table 1.

[0047] Table 1

[0048] It can be seen from Table 1 that the glass transition temperatures of samples AF are relatively low, significantly lower than that of perfluoroether rubber, which indicates that the chain-functionalized perfluoropolyether prepared in the present invention can significantly improve the low-temperature performance of perfluoroether rubber.

Claims

1. A method for preparing a chain-functionalized perfluoropolyether, characterized in that: include: S1, mixing a double-terminated hydroxyl perfluoropolyether, an oxidizing agent, and a solvent to obtain an oxidation product, and mixing the oxidation product with an alcohol to obtain a first intermediate product; S2, mixing an acetyl compound, a hydrogen extraction reagent, and an ether solvent to react to obtain a second intermediate product containing a carbon anion; S3, mixing the first intermediate product and the second intermediate product, reacting them, and separating the products to obtain the in-chain functionalized perfluoropolyether.

2. The preparation method according to claim 1, characterized in that: In S1, the reaction temperature is 60-120° C. and the reaction time is 1-72 h.

3. The preparation method according to claim 1, characterized in that: In S2, the reaction temperature is 0-60°C and the reaction time is 0.2-5h.

4. The preparation method according to claim 1, characterized in that: In S3, the reaction temperature is 25-120° C. and the reaction time is 0.5-36 h.

5. The preparation method according to claim 1, characterized in that: The average molecular weight of the double-terminated hydroxyl perfluoropolyether is 1000-10000.

6. The preparation method according to claim 1, characterized in that: The alcohol includes methanol and / or ethanol.

7. The preparation method according to claim 1, characterized in that: The dihydroxyl-terminated perfluoropolyether includes one or a combination of two or more of dihydroxyl-terminated K-type perfluoropolyether, dihydroxyl-terminated Y-type perfluoropolyether and dihydroxyl-terminated Z-type perfluoropolyether.

8. The preparation method according to claim 1, characterized in that: The acetyl compound includes one or a combination of two or more of halogenated ethyl acetate, halogenated methyl acetate, ethyl acetate, methyl acetate, halogenated acetone, acetone, halogenated ethyl malonate, halogenated methyl malonate, ethyl malonate, and methyl malonate.

9. The preparation method according to claim 1, characterized in that: The oxidizing agent includes one or a combination of two or more of potassium permanganate, potassium dichromate, sodium dichromate, chromium trioxide, potassium peroxymonosulfonate, nitric acid, oxygen, hydrogen peroxide, dimethyl sulfoxide-dicyclohexylcarbodiimide complex, and sodium perchlorate.

10. The preparation method according to claim 1, characterized in that: The hydrogen extraction reagent includes one or a combination of two or more of sodium methoxide, sodium ethoxide, sodium isopropoxide, potassium tert-butoxide, sodium hydride, potassium hydride, lithium diisopropylamide, n-butyl lithium, and sec-butyl lithium.

11. The preparation method according to claim 1, characterized in that: The ether solvent includes one or a combination of two or more of tetrahydrofuran, dioxane, methyl tert-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether.

12. The preparation method according to claim 1, characterized in that: The molar ratio of the double-terminated hydroxyl perfluoropolyether to the oxidizing agent is 1:1-10.

13. The preparation method according to claim 1, characterized in that: The molar ratio of the acetyl compound to the hydrogen extraction agent is 1:0.9-3.

14. A mid-chain functionalized perfluoropolyether prepared by the preparation method according to any one of claims 1 to 13.

15. A perfluoropolyether-based elastomer, characterized in that: The polyfluorocarbon is obtained by cross-linking the chain-functionalized perfluoropolyether as claimed in claim 14.

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