CN113667051B

CN113667051B - Preparation method of high-hydrophobicity oleophobic emulsion containing perfluoropolyether structure

Info

Publication number: CN113667051B
Application number: CN202111072416.0A
Authority: CN
Inventors: 靳琳琳; 杨卫东; 沈晓炜; 朱建军; 姚英铭; 丁伟; 王琳; 钱梦琦
Original assignee: Satellite Chemical Co ltd
Current assignee: Satellite Chemical Co ltd
Priority date: 2021-09-13
Filing date: 2021-09-13
Publication date: 2022-07-15
Anticipated expiration: 2041-09-13
Also published as: CN113667051A

Abstract

The invention discloses a preparation method of a high hydrophobic and oleophobic emulsion containing short-chain perfluoroalkyl, which takes water as a solvent, a perfluoropolyether functional monomer PFPEA and an acrylic monomer without a perfluoro long-chain alkyl structure are added with an initiator under the conditions of an emulsifier, a cross-linking agent and an assistant stabilizer, and a monomer copolymer is synthesized through miniemulsion polymerization. The coating has excellent hydrophobic and oleophobic performances on substrates such as glass, wood, steel plates, plastics and the like. The high-hydrophobicity oleophobic emulsion prepared by the method does not contain a perfluoro long-chain alkyl structure, has the advantage of easy degradation, is environment-friendly, and meets the requirement of green chemistry.

Description

Preparation method of high-hydrophobicity oleophobic emulsion containing perfluoropolyether structure

Technical Field

The invention belongs to the technical field of special coating, and particularly relates to a preparation method of a high-hydrophobicity oleophobic emulsion containing a perfluoropolyether structure.

Background

In nature, many animals and plants have unique shapes and structures for adapting to the natural environment, such as rose petals, rice leaves, which allow water drops to roll completely, and unique water repellency of a water strider which can freely walk on the water surface. Inspired by this, hydrophobic materials are being continuously studied and developed. However, with the development of research, it has been observed that when a hydrophobic surface is contacted with a liquid having a low surface tension, such as oil stain, n-hexadecane, etc., the hydrophobic surface is easily contaminated due to the spreading of liquid droplets, thereby limiting the self-cleaning function. By combining the characteristic research of the hydrophobic bionic surface and the oleophobic bionic surface, the double hydrophobic surfaces theoretically can perfectly solve the self-cleaning problem of the material in the oil-water coexistence environment.

The double-hydrophobic surface has wide application in self-cleaning, oil-water separation, antifouling, antifogging, anti-icing, drag reduction, organic liquid transportation, anticorrosion and other aspects. While being a double hydrophobic surface capable of repelling liquids over a wide range of surface tensions requires a very low surface energy component.

Long fluorocarbon chain (C)_nF_2n+1N is more than or equal to 8) can reduce the surface tension of the base material to 10-15mN/m, and has excellent waterproof and oilproof effects. However, with the use of a large amount of long fluorocarbon chain-containing polymers, environmental problems caused by the long fluorocarbon chain-containing polymers have attracted much attention. The European Union Perfluorooctylsulfonyl (PFOS) ban requires that the PFOS or related substances thereof have a PFOS content of not more than 1 μ g/m in textile or coating materials². As regards perfluorooctanoic compounds (PFOA), which are also known to have PFOS-like hazards, zero emission has also been required at present.

Chinese patent CN108517161A discloses a super-hydrophobic oleophobic coating and a preparation method thereof. Stirring the mixture of water, inorganic weak base, glycol homologues, alkylphenol polyoxyethylene ether emulsifier, sulfonate and/or sulfate type anionic emulsifier, crosslinking monomer and crosslinking initiator to obtain milky stable pre-emulsion; reacting the milky stable pre-emulsion at 40-90 ℃ for 1-8 h, cooling, and adjusting the pH value to 7-8 by ammonia water to obtain a silicone-acrylate emulsion; uniformly stirring the silicone-acrylic emulsion, the alcohol solvent, the ethyl orthosilicate and the ammonia water, heating to 40-80 ℃ and reacting for 1-10 h to obtain a cohydrolysis condensation suspension; adding perfluoroalkyl triethoxysilane and/or perfluoroalkyl trimethoxysilane into the cohydrolysis-condensation suspension, and reacting at 50-70 deg.C for 0.5-8 h to obtain the super hydrophobic and oleophobic coating. The super-hydrophobic oleophobic coating is simple to prepare and has good super-hydrophobic oleophobic properties. Also disclosed are super-hydrophobic and oleophobic coating films based on the coatings. However, the whole synthesis process is complicated, and the used perfluoroalkyl triethoxysilane and/or perfluoroalkyl trimethoxysilane contain long-chain alkyl, which causes harm to the environment.

Chinese patent CN108659723A discloses a hydrophobic and oleophobic functional membrane and a preparation method thereof. The hydrophobic and oleophobic functional membrane is composed of a base membrane, a hydrophobic and oleophobic layer, an adhesive layer and a release layer, wherein the hydrophobic and oleophobic layer is arranged on one side of the base membrane, and the adhesive layer and the release layer are sequentially arranged on the other side of the base membrane; the preparation process of the hydrophobic and oleophobic layer comprises the following steps: preparing a graphene oxide ethanol solution with the concentration of 2mg/mL by using ethanol as a solvent, adjusting the pH value to 9 by using ammonia water, and adding a perfluoro long-chain silane coupling agent, wherein the mass ratio of the perfluoro long-chain silane coupling agent to the graphene oxide is 1: refluxing at 1 and 60 ℃ for 24 hours; soaking the basement membrane in the solution for 5h, taking out and drying by air blast. And then soaking the basement membrane in a solution prepared by mixing hydrazine hydrate and water according to the volume ratio of 1: 30 ml of hydrazine hydrate aqueous solution, and reducing the solution at 80 ℃ for 2 h. Although the prepared protective film has better protective performance on water stains and oil stains and can play a good role in protecting the operating table top of a base plate of mechanical equipment, the selected perfluoro long-chain silane coupling agent is heptadecafluorodecyltriethoxysilane, which has potential threat to the natural environment.

Chinese patent CN108659723A discloses a method for preparing super-hydrophobic emulsion containing short fluorinated alkyl, which comprises using water as solvent, functional monomer BRFAE containing branched chain high-fluorine carbon alcohol group structure and acrylic acid monomer, under the condition of emulsifier, cross-linking agent and co-stabilizer, adding initiator, and polymerizing at 40-85 deg.C by miniemulsion to synthesize monomer copolymer, wherein the prepared coating has excellent hydrophobic property, but the functional monomer containing branched chain high-fluorine carbon alcohol group structure has low fluorine content, and the C is C₄F has a short fluorocarbon side chain, i.e., it does not crystallize, nor does it constitute a stable liquid crystal, and when contacted with a non-polar substance,the short chain containing F is reconstructed, the coating effect on the substrate is weakened, and a compact protective film cannot be formed on the surface of the substrate, so that the coating prepared from the F-containing short chain has poor oleophobic performance.

Fluorine-containing materials have excellent hydrophobic and oleophobic properties, but the limited use of long-chain perfluorocarbons restricts the development of high-performance amphiphobic coatings. Therefore, the invention provides a perfluoropolyether functional monomer PFPEA which has high fluorine content and meets the requirement of green chemistry.

Disclosure of Invention

The invention aims to solve the problem that the use of fluorine-containing reagents is limited in the existing preparation method of the double-hydrophobic coating, break through the conventional thinking, synthesize a series of functional monomers PFPEA with a perfluoropolyether structure by adopting a solvent method, and provide a green and environment-friendly preparation method of the high-hydrophobicity and oleophobic emulsion with the perfluoropolyether structure. With short-chain branches C₄Compared with the F phase, the PFPEA in the invention connects short fluorocarbon chains through ether bonds, so that the whole molecular chain segment is lengthened, and the prepared emulsion has the hydrophobic and oleophobic performances.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of a high hydrophobic and oleophobic emulsion containing a perfluoropolyether structure is characterized in that water is used as a solvent, a perfluoropolyether functional monomer PFPEA and an acrylic monomer which do not contain a perfluoro long-chain alkyl structure are added with an initiator under the conditions of an emulsifier, a cross-linking agent and a co-stabilizer, the mixture reacts for 2 to 6 hours at 70 to 90 ℃, and a monomer copolymer is synthesized through miniemulsion polymerization;

wherein, the contents of all substances are calculated by weight percent as follows:

further, the perfluoropolyether functional monomer PFPEA does not contain a perfluoro long-chain alkyl structure and is one or more of the following substances:

wherein n is the degree of polymerization, R₁Is a perfluoroalkyl group, R₂Is a group with double bonds.

The fluorine-containing monomer PFPEA has a perfluoropolyether structure, short-chain fluorine-containing groups are connected through ether bonds, and the whole molecular size is determined by the polymerization degree n. Although an increase in the degree of polymerization n can increase the F content, the reaction conditions in the emulsion polymerization are more severe. Preferably, the degree of polymerization n is 1 or 2.

Said R is₁Is a perfluoroalkyl radical, preferably C, according to green chemistry₁-C₆Of (a) a perfluoroalkyl group, said group being in particular CF₃CF₂-、CF₃CF₂CF₂-、CF₃CF₂CF₂CF₂-、(CF₃)₃CCF₂CF₂-、CF₃CF₂CF(CF₃)CF₂And (c) an isoperfluoroalkyl group.

The R is₂The double bond group may be a group providing a double bond to the entire PFPEA monomer, and the F-containing monomer may be introduced into the emulsion by polymerization, and may be selected from a group containing a C ═ C double bond such as propylene, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, and the like, and is preferably a group containing propylene, acrylic ester, methacrylic ester, and the like.

The perfluoropolyether functional monomer PFPEA is specifically one or more of the following substances:

5H,5H-4,7, 10-undecoxyloxypropene (PFPEA-1):

5H,5H-4,7,10, 13-pentadecafluoroalkoxypropene (PFPEA-2):

5H,5H-6, 9-diperfluoromethyl-4, 7, 10-undecafluoro alkoxy propene (PFPEA-3):

5H,5H-6,9, 12-Triperfluoromethyl-4, 7,10, 13-Tetradecafluoroalkoxypropene (PFPEA-4):

5H,5H-4,7, 10-pentadecafluoroalkoxypropene (PFPEA-5):

5H,5H-4,7,10, 13-nonadecafluoroalkoxy-2-methacrylate (PFPEA-6):

5H,5H-13, 13-Biperfluoromethyl-4, 7, 10-perfluoroalkoxy-2-methacrylate (PFPEA-7):

5H,5H-6,9,12, 15-Tetraperfluoromethyl-4, 7,10, 13-perfluoroalkoxy-2-methacrylate (PFPEA-8):

further, the perfluoropolyether functional monomer PFPEA is preferably PFPEA-8.

Further, the following raw materials in percentage by weight are adopted:

further, the functional monomer PFPEA-1 is prepared by the following method:

dissolving 95.7g of tetrafluorooxirane and 2.0g of potassium fluoride in 150mL of diethylene glycol dimethyl ether, introducing nitrogen, reacting for 10h under ice bath conditions, heating to 30 ℃, adding 9.6g of methanol, reacting for 4h, and removing the solvent to obtain a product, namely perfluoropolyether methyl ester (CF)₃CF₂OCF₂CF₂OCF₂COOCH₃)；

80g of the product perfluoropolyether methyl ester (CF) described above₃CF₂OCF₂CF₂OCF₂COOCH₃) Adding 100mL of ethanol as a solvent, adding 5g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂OCF₂CF₂OCF₂CH₂OH)；

49.8g of perfluoropolyether alcohol (CF)₃CF₂OCF₂CF₂OCF₂CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), reacted at 70 ℃ for 30min under nitrogen, added 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-1, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-2 is prepared by the following steps:

127.7g of tetrafluorooxirane and 2.0g of potassium fluoride are dissolved in 150mL of diethylene glycol dimethyl ether, nitrogen is introduced, the mixture reacts for 10h under ice bath conditions, the temperature is raised to 30 ℃, 9.6g of methanol is added, the reaction is carried out for 4h, and the solvent is removed, so that the product perfluoropolyether methyl ester (CF) is obtained₃CF₂OCF₂CF₂OCF₂CF₂OCF₂COOCH₃)；

80g of the product perfluoropolyether methyl ester (CF)₃CF₂OCF₂CF₂OCF₂CF₂OCF₂COOCH₃) Adding 100mL of ethanol as a solvent, and adding 5g of sodium borohydrideReacting for 4 hours at 25 ℃ to obtain the product of perfluoropolyether alcohol (CF)₃CF₂OCF₂CF₂OCF₂CF₂OCF₂CH₂OH)；

67.2g of perfluoropolyether alcohol (CF)₃CF₂OCF₂CF₂OCF₂CF₂OCF₂CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), reacted at 70 ℃ for 30min under nitrogen, added 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-2, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-3 is prepared by the following method:

149.9g of hexafluoropropylene oxide and 2.0g of potassium fluoride are dissolved in 300mL of diethylene glycol dimethyl ether, nitrogen is introduced, the mixture reacts for 10 hours under ice bath conditions, the temperature is raised to 30 ℃, 9.6g of methanol is added, the reaction is carried out for 4 hours, and the solvent is removed, so that the product perfluoropolyether methyl ester (CF) is obtained₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)-COOCH₃)；

100g of the product perfluoropolyether methyl ester (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)COO-CH₃) Adding 150mL of ethanol as a solvent, adding 8g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CH₂OH)；

72.3g of perfluoropolyether alcohol (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), purged with nitrogen, reacted at 70 ℃ for 30min, added with 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-3, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-4 is prepared as follows:

199.9g of hexafluoropropylene oxide, 2.0g of potassium fluoride were dissolved in 300mL of diethylene glycol dimethylIntroducing nitrogen into ether, reacting for 10h under ice bath condition, heating to 30 ℃, adding 9.6g of methanol, reacting for 4h, and removing the solvent to obtain the product perfluoropolyether methyl ester (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)COOCH₃)；

100g of the product perfluoropolyether methyl ester (CF) described above₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)COOCH₃) Adding 150mL of ethanol as a solvent, adding 8g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)CH₂OH)；

97.2 g perfluoropolyether alcohols (CF)₃CF₂CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)-CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), reacted at 70 ℃ for 30min under nitrogen, added 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-4, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-5 is prepared by the following steps:

immersing 2.9g of magnesium powder in 20mL of anhydrous ether, slowly dropping 150mL of anhydrous ether dissolved with 44.7g of perfluoroalkyl iodide, reacting in a water bath at 60 ℃, reacting for 30min after dropping, and preparing the Grignard reagent CF₃CF₂MgI；

95.7g of tetrafluoroethyleneoxide, 2.0g of potassium fluoride and 29.8g of Grignard CF prepared as described above₃CF₂Dissolving MgI in 150mL diethylene glycol dimethyl ether, introducing nitrogen, reacting for 10h under ice bath condition, heating to 30 ℃, adding 9.6g methanol, reacting for 4h, removing the solvent to obtain the product perfluoropolyether methyl ester (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂COOCH₃)；

80g of the product perfluoropolyether methyl ester (CF) described above₃CF₂CF₂CF₂OCF₂CF₂OCF₂COOCH₃) Adding 100mL of ethanol as a solvent, adding 5g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CH₂OH)；

64.8g of perfluoropolyether alcohol (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CF₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), purged with nitrogen, reacted at 70 ℃ for 30min, added with 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-5, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-6 is prepared as follows:

127.7g of tetrafluoroethane oxide, 2.0g of potassium fluoride and 29.8g of Grignard CF prepared above₃CF₂Dissolving MgI in 150mL diethylene glycol dimethyl ether, introducing nitrogen, reacting for 10h under ice bath condition, heating to 30 ℃, adding 9.6g methanol, reacting for 4h, removing the solvent to obtain a product perfluoropolyether methyl ester (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CF₂OCF₂COOCH₃)；

80g of the product perfluoropolyether methyl ester (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CF₂OCF₂COO-CH₃) Adding 100mL of ethanol as a solvent, adding 5g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CH₂OCF₂CH₂OH)；

82.2g of perfluoropolyether alcohol (CF)₃CF₂CF₂CF₂OCF₂CF₂OCF₂CH₂OCF₂CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), purged with nitrogen, reacted at 70 ℃ for 30min, added with 11.5g chloropropene, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged off and the product, the functional monomer PFPEA-6, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-7 is prepared by the following steps:

35.4g of perfluoro-tert-butanol ((CF)₃)₃COH) was reacted with 12.3g hydrobromic acid in 100mL ethanol for 2h to prepare (CF)₃)₃And (4) CBr. 2.9g of magnesium powder was immersed in 20mL of anhydrous diethyl ether, and 35.9g (CF) was slowly dropped into 150mL of the solution₃)₃Reacting CBr anhydrous ether in water bath at 60 ℃, reacting for 30min after finishing dripping, and preparing Grignard reagent (CF)₃)₃CMgBr；

95.7g of tetrafluoroethyleneoxide, 2.0g of potassium fluoride and 32.3g of Grignard reagent (CF) prepared as described above₃)₃CMgBr was dissolved in 150mL diethylene glycol dimethyl ether, nitrogen was introduced, the reaction was carried out for 10h in an ice bath, the temperature was raised to 30 ℃, 9.6g methanol was added, the reaction was carried out for 4h, and the solvent was removed to obtain the product perfluoropolyether methyl ester ((CF)₃)₃CCF₂CF₂OCF₂CF₂OCF₂COOCH₃)；

80g of the above-mentioned product perfluoropolyether methyl ester ((CF)₃)₃CCF₂CF₂OCF₂CF₂OCF₂COOCH₃) Adding 100mL of ethanol as a solvent, adding 5g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product of perfluoropolyether alcohol ((CF)₃)₃CCF₂CF₂OCF₂CF₂OCF₂CH₂OH)；

79.8g of perfluoropolyether alcohol ((CF)₃)₃CCF₂CF₂OCF₂CF₂OCF₂CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), purged with nitrogen, reacted at 70 ℃ for 30min, 15 added7g of methacryloyl chloride, at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-7, was precipitated with diethyl ether.

Further, the functional monomer PFPEA-8 is prepared by the following method:

199.9g of hexafluoropropylene oxide, 2.0g of potassium fluoride and 29.8g of the Grignard reagent CF prepared above₃CF₂Dissolving MgI in 300mL diethylene glycol dimethyl ether, introducing nitrogen, reacting for 10h under ice bath condition, heating to 30 ℃, adding 9.6g methanol, reacting for 4h, removing the solvent to obtain the product perfluoropolyether methyl ester (CF)₃CF₂CF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)COOCH₃)；

100g of the product perfluoropolyether methyl ester (CF) described above₃CF₂CF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)CF₂OCF(CF₃)COOCH₃) Adding 150mL of ethanol as a solvent, adding 8g of sodium borohydride, and reacting at 25 ℃ for 4h to obtain the product perfluoropolyether alcohol (CF)₃CF₂CF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)CF₂OCF(CF₃)CH₂OH)；

112.2g of perfluoropolyether alcohol (CF)₃CF₂CF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)CF₂O-CF(CF₃)CH₂OH), 15.2g Triethylamine (TEA), dissolved in 100mL Methyl Ethyl Ketone (MEK), purged with nitrogen, reacted at 70 ℃ for 30min, added with 15.7g methacryloyl chloride, and reacted at 70 ℃ for 3 h. Cooled to room temperature and stirred overnight. The TEA-HCl salt was centrifuged and the product, PFPEA-8, was precipitated with diethyl ether.

Further, the acrylic monomer is one or more of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate and methyl methacrylate.

Further, the initiator is one or more of azobisisobutyronitrile, potassium persulfate, ammonium persulfate, azobisisobutyramidine hydrochloride, azobisisobutyronitrile or azobiscyanovaleric acid.

Further, the co-stabilizer is one or more of n-hexadecane, octadecyl methacrylate, hexadecyl methacrylate, cetyl polystyrene, polyvinyl acetate and vinyl decanoate.

Further, the cross-linking agent is one or more of dicumyl peroxide (DCP), di-tert-butyl peroxide (DTBP), 2, 5-dimethyl-2, 5-di-tert-butyl peroxy hexane (bis 25), methyl trimethoxy silane, methyl triethoxy silane, vinyl trimethoxy silane and vinyl triethoxy silane.

Further, the emulsifier is one or more of Sodium Dodecyl Benzene Sulfonate (SDBS), alkylphenol polyoxyethylene ether (OP-10), Sodium Vinyl Sulfonate (SVS), 2-allyl ether-3-hydroxypropyl alkyl-1-sodium sulfonate (UCAN-1), allyl ether hydroxy propane sodium sulfonate (UCAN-8088), alcohol ether succinate sodium salt (NRS-138) and acrylamide isopropyl sulfonate (A-2405).

Compared with the prior art, the invention has the following beneficial effects:

the F element in the emulsion prepared by the invention is provided by the functional monomer PFPEA containing a perfluoropolyether structure, and the fluorine content is high. Multiple short fluorocarbon chains in PFPEA connected by ether linkages to C₄Compared with F, the whole molecular chain segment is longer, and the liquid crystal performance is better, so that after a coating is formed, a fluorocarbon chain in PFPEA is not reconstructed, a compact protective film can be well formed to cover the surface of a substrate, and excellent hydrophobic and oleophobic performances are shown. Ether bonds in the PFPEA are easy to degrade, and degraded products are short fluorocarbon chain substances, so that the PFPEA is environment-friendly and meets the requirement of green chemistry.

Drawings

FIG. 1 is a schematic view ofPreparation of 5H,5H-13, 13-Biperfluoromethyl-4, 7, 10-perfluoroalkoxy-2-methacrylate (PFPEA-7) in inventive example 7¹HNMR picture.

FIG. 2 is a drawing showing the preparation of 5H,5H-13, 13-diperfluoromethyl-4, 7, 10-perfluoroalkoxy-2-methacrylate (PFPEA-7) in example 7 of the present invention¹⁹FNMR map.

FIG. 3 is a drawing showing the preparation of 5H,5H-6,9,12, 15-tetraperfluoromethyl-4, 7,10, 13-perfluoroalkoxy-2-methacrylate (PFPEA-8) in example 8 of the present invention¹HNMR map.

FIG. 4 is a drawing of 5H,5H-6,9,12, 15-tetraperfluoromethyl-4, 7,10, 13-perfluoroalkoxy-2-methacrylate (PFPEA-8) in example 8 of the present invention¹⁹FNMR map.

FIG. 5 is a graph showing the effect of the emulsions prepared in examples 1 to 8 of the present invention and comparative examples 1 to 2 on the hydrophobic and oleophobic properties of fabrics tested with water, orange juice, coffee, milk, salad oil, and Hexadecane (HD) to form coatings.

Detailed Description

Embodiments of the present invention are further illustrated by the following examples.

Example 1

10.0g of butyl acrylate, 10.0g of methyl methacrylate, 10.0g of the product PFPEA-1 prepared above, 1.0g of n-hexadecane as a co-stabilizer, 1.0g of methyltrimethoxysilane as a crosslinking agent, 1.0g of sodium allyl ether hydroxypropanesulfonate (UCAN-8088) as an emulsifier, 0.1g of potassium persulfate (KPS) as an initiator and the balance of water (the weight percentages of the raw materials are shown in the following table) are added into a beaker, and ultrasonic treatment is carried out in an ultrasonic cell crusher for 3s under ice bath conditions, the batch is carried out for 5s, and the duration is kept for 15 min. And (3) filling the obtained pre-emulsion into a four-neck flask, purging with nitrogen for 30min, and reacting at 80 ℃ for 3h to obtain the copolymer emulsion.

The weight percentage of each substance in the raw material of the example 1 is shown in the following table 1:

TABLE 1

Raw materials	Weight percent of
		PFPEA-1	5％
Acrylic acid butyl ester	5％
		Methacrylic acid methyl ester	5％
N-hexadecane	0.5％
		Methyltrimethoxysilane	0.5％
UCAN-8088	0.5％
		KPS	0.05％
Water (W)	Balance of

Examples 2 to 8

In examples 2 to 8, PFPEA-1 in example 1 was replaced with PFPEA-2 to 8, respectively, and copolymer emulsions were prepared in the same manner as in example 1, except that the conditions were changed.

In comparative example 1, PFPEA1 was not added and copolymer emulsion was prepared in the same manner as in example 1, except that the conditions were not changed.

In comparative example 2, PFPEA-1 in example 1 was replaced with BRFAE, a functional monomer having a high fluorocarbon alcohol group structure, and the copolymer emulsion was prepared in the same manner as in example 1, except that the conditions were not changed.

The emulsions prepared in the above examples and comparative examples were subjected to a hydrophobicity test as follows: the surface energy of the emulsion obtained is tested by a surface tension meter, and the emulsion is sprayed on wood, steel plates, glass and PVC plates by a spin coater to test the contact angle of water and oil (HD).

Table 2 shows the surface energy and contact angle data of water and oil (HD) on glass, steel plate, wood, PVC plate of examples 1 to 8 of the present invention and comparative examples 1 to 2, in which example 8 is the most preferable example. As can be seen from the data in the table, compared with comparative example 1, after the perfluoropolyether functional monomer PFPEA is added into the emulsion, the surface energy of the emulsion is reduced, and the hydrophobic and oleophobic properties of the coating are obviously improved; compared with comparative example 2, the added perfluoropolyether functional monomer improves CF in short-chain perfluoroalkyl₃The bulk density of the groups on the surface of a substrate is lower, the surface energy is lower, O atoms are inserted into a molecular skeleton, and a short-chain perfluoroalkyl group with a carbon chain length of 4 or 6 is used for replacing 8-carbon PFOA and PFOS, so that the effective length of a fluorine-containing chain segment is reduced, the advantage of easy degradation is achieved, the whole fluorine carbon chain of the perfluoropolyether is longer, the surface of the prepared coating is not easy to reconstruct, and the prepared coating has good hydrophobic and oleophobic properties.

FIGS. 1 to 4 are a 1HNMR map and a 19FNMR map of PFPEA-7 in example 7 and a 1HNMR map and a 19FNMR map of PFPEA-8 in example 8, respectively, according to the present invention, and the characterization results are consistent with the structures of the products. FIG. 5 is a graph showing the effect of the emulsions prepared in examples 1 to 8 of the present invention and comparative examples 1 to 2 on the coating of a woven fabric, and the water and oil repellency of the fabric is measured by water, orange juice, coffee, milk, salad oil, and Hexadecane (HD), and it is further verified that the emulsion containing a perfluoropolyether structure prepared by the present invention has excellent water and oil repellency in accordance with the results of the measurement in Table 1.

TABLE 2

Examples 9-12, based on example 8, the amounts of PFPEA8 were adjusted to 15%, 12%, 3%, and 20%, respectively, and the copolymer emulsions were prepared in the same manner as in example 8, except that the conditions were not changed.

The emulsions prepared in the above examples and comparative examples were subjected to a hydrophobicity test as follows: the obtained emulsion is used for testing the surface energy by a surface tensiometer, and the emulsion is sprayed on wood, steel plates, glass and PVC plates by a spin coater to test the contact angle of water and oil (HD). The test results are shown in table 3.

TABLE 3

From the physical property data in Table 3, it is clear that the perfluoropolyether copolymerized acrylic emulsion prepared in examples 8 to 10 has excellent water and oil repellency, and the content of perfluoropolyether is too low in example 11, and CF is contained in short-chain perfluoroalkyl group₃The bulk density of the groups on the surface of the substrate is small, so the surface energy is higher, the hydrophobic and oleophobic effect cannot be achieved, the content of perfluoropolyether in example 12 is large, but the hydrophobic and oleophobic effect is poor due to excessive CF₃The structural and restructuring phenomena of the group aggregation on the surface of the copolymer chain cause that the larger the value of n in the formula (I), the poorer the water and oil repellency, and the use amount of the perfluoropolyether compound expressed by the formula (I) is 5-15%, preferably 12%, which has unexpected effects.

Claims

1. A preparation method of a high-hydrophobicity oleophobic emulsion containing a perfluoropolyether structure is characterized in that water is used as a solvent, a perfluoropolyether functional monomer PFPEA and an acrylic monomer which do not contain a perfluoro long-chain alkyl structure are added with an initiator under the conditions of an emulsifier, a cross-linking agent and a co-stabilizer, the reaction is carried out for 2 to 6 hours at 70 to 90 ℃, and a monomer copolymer is synthesized through miniemulsion polymerization;

wherein, the contents of all the substances are calculated by weight percent as follows:

perfluoropolyether functional monomer PFPEA 5-15%

Acrylic monomer 10-30%

0.5 to 5 percent of emulsifier

0.5 to 5 percent of cross-linking agent

0.5 to 5 percent of assistant stabilizer

0.05 to 1 percent of initiator

The balance of water;

the functional perfluoropolyether monomer PFPEA is as follows:

5H,5H-4,7, 10-pentadecafluoroalkoxypropene

The acrylic monomer is one or more of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate and methyl methacrylate.

2. The method of claim 1, wherein the amounts of each of the substances are as follows in weight percent

Perfluoropolyether functional monomer PFPEA 5%

Acrylic acid monomer 10%

0.5 percent of emulsifier

0.5 percent of cross-linking agent

0.5 percent of co-stabilizer

0.05 percent of initiator

The balance of water.

3. The method of claim 1, wherein the initiator is one or more of azobisisobutyronitrile, potassium persulfate, ammonium persulfate, azobisisobutyramidine hydrochloride, azobisisobutyrimidazoline, or azobiscyanovaleric acid.

4. The method of claim 1, wherein the co-stabilizer is one or more of n-hexadecane, octadecyl methacrylate, hexadecyl methacrylate, cetyl polystyrene, polyvinyl acetate, and vinyl decanoate.

5. The method of claim 1, wherein the crosslinking agent is one or more of dicumyl peroxide (DCP), di-t-butyl peroxide (DTBP), 2, 5-dimethyl-2, 5-di-t-butylperoxyhexane (bis 25), methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

6. The method of claim 1, wherein the emulsifier is one or more of Sodium Dodecylbenzenesulfonate (SDBS), alkylphenol ethoxylate (OP-10), Sodium Vinylsulfonate (SVS), sodium 2-allyl ether-3-hydroxypropylalkane-1-sulfonate (UCAN-1), sodium allyl ether hydroxypropanesulfonate (UCAN-8088), sodium alcohol ether succinate (NRS-138), acrylamido isopropyl sulfonate (a-2405).