Fluorine-containing acrylate organic nano-microsphere with high fluorine content as well as synthesis method and application of fluorine-containing acrylate organic nano-microsphere

Abstract

The invention discloses a fluorine-containing acrylate organic nano-microsphere with high fluorine content and a synthetic method and application thereof, and the synthetic method comprises the following steps: (1) carrying out emulsion polymerization on a raw material containing a fluorine-containing emulsifier and a fluorine-containing acrylate monomer to obtain a fluorine-containing acrylate emulsion; and (2) carrying out demulsification, separation, drying and grinding on the fluorine-containing acrylate emulsion to obtain the fluorine-containing acrylate organic nano microspheres with high fluorine content. Firstly, micelles can be formed in water through the emulsifier with a special structure, hydrophilic and hydrophobic ends can be effectively balanced and stabilized through interaction force among fluorine atoms and existence of ether bonds, and the wrapping capacity on fluorine-containing monomers is improved. The hydrophobic end of the emulsifier used in the invention has good compatibility with the pre-polymerized monomer, and the problem of poor compatibility of the fluorine-containing monomer can be solved.

Description

Technical Field

[0001] The present invention relates to the field of synthesis and preparation of polymer materials, and particularly to a fluorinated acrylate organic nano - microsphere with a high fluorine content, its synthesis method and application. Background Art

[0002] Due to its unique chemical structure (strong C - F bond, low surface energy), fluorinated acrylate has irreplaceable advantages in hydrophobic and oleophobic aspects, such as chemical pipelines, platinum boat antifouling, fluorinated hydrophobic coatings, etc. In addition, due to its excellent dielectric properties, fluorinated acrylate polymers are widely used in the insulation of wires and cables. This property enables the signal strength to be minimized during transmission. Therefore, due to the ability of fluorinated polymers to adapt to various harsh conditions, they are widely used in various fields such as electrical, mechanical, chemical industry, and automotive.

[0003] The polymerization of fluorinated acrylate is generally carried out by copolymerizing fluorinated acrylate monomers with other olefin monomers. The main synthetic routes are solution polymerization and emulsion polymerization.

[0004] Solution polymerization is the main route for preparing fluorinated polyacrylate resins. The polymerization method is simple, the conditions are easy to control, and high - temperature conditions are not required during use. However, due to the presence of a large amount of organic solvents in the fluorinated acrylate copolymers prepared by solution polymerization, their applications are restricted in many ways. In particular, the flash points of some solvents are relatively low, posing safety hazards and requiring additional protective measures. At the same time, the high price of fluorinated solvents leads to too high production costs. In addition, for solution polymerization, the required monomers need to be added to a suitable solvent, and the monomers are fully dissolved by heating and stirring before polymerization. For fluorinated acrylate, due to the stable bond energy and strong polarity of the carbon - fluorine bond, when the content of fluorine monomers in the acrylate system increases, phase separation occurs with most solvents, and the monomers cannot be dissolved, making the polymerization reaction difficult to proceed. Emulsion polymerization is a process where monomers are dispersed in water to form an emulsion with the help of an emulsifier and mechanical stirring, forming emulsion micelles in the dispersion medium. Then an initiator is added, and through the continuous collision of free radicals inside and between the micelles, chain polymerization of the monomers is initiated. By reasonably regulating the structure and proportion of the emulsifier, successful loading of a high fluorine content in the polymer can be achieved. In addition, the polymerization rate of fluorinated polyacrylate prepared by emulsion polymerization is fast, the polymerization efficiency is high, the particle size of fluorinated acrylate latex particles can be controlled by changing the polymerization process, the reaction temperature is easy to control, and emulsion polymerization uses water as the reaction medium, avoiding environmental pollution caused by organic solvents.

[0005] In the traditional emulsion polymerization process, the emulsifier is physically adsorbed on the surface of latex particles. However, in fluoroacrylate, the carbon-fluorine bond has the characteristics of stable chemical bond energy and strong polarity. When the content of fluoroacrylate monomer in the emulsion polymerization system increases, due to the difference in solubility parameters, the monomer is prone to demulsification, flocculation and other characteristics, thus affecting the performance of the polymer. In traditional emulsion polymerization, OP-10 and SDS emulsifiers are generally used in combination for emulsion polymerization reaction, and the content of fluorine monomer is generally below 50%.

[0006] For fluorinated polymer materials, the phase separation of fluorine is mainly caused by the difference in surface tension between fluorinated groups and non-fluorinated groups in the polymer main chain. However, the entanglement of polymer chains and the chain segment movement ability often seriously hinder the migration of fluorinated groups from the inside to the surface, so the expected hydrophobicity and dielectric properties cannot be obtained. Therefore, the amount of fluorine monomer used will greatly affect the application of fluoroacrylate powder in hydrophobic and oleophobic, low dielectric aspects.

[0007] At present, the amount of fluorine monomer used in the prior art to prepare fluoroacrylate is relatively small, only 10wt% - 20wt%. Its improvement of performance amplitude is limited. High-fluorine-content fluoroacrylate has not been successfully prepared, and the influence of the amount of fluorine monomer used on the particle size, hydrophobic and oleophobic properties, and dielectric properties of fluoroacrylate powder has not been explored. Summary of the Invention

[0008] In view of the problems in the background technology, the present invention specifically relates to a synthesis method of fluoroacrylate organic nano-microspheres with high fluorine content: First, through an emulsifier with a special structure, micelles can be formed in water. The mutual force between fluorine atoms and the existence of ether bonds will effectively balance and stabilize the hydrophilic and hydrophobic ends, improving the encapsulation ability of fluorine monomers. The hydrophobic end of the emulsifier used in the present invention has good compatibility with the prepolymer monomer, which can solve the problem of poor compatibility of fluorine monomers. In emulsion polymerization, the emulsifier is adsorbed on the latex particles, and the hydrophilic end extends into the water phase, making the latex particles stable through intermolecular interaction and steric hindrance effect, thereby improving the storage stability of the emulsion. In the process of fluoroacrylate emulsion polymerization using an emulsifier with a special structure, the present invention successfully increases the content of fluorine monomer to more than 70%, solves the problems of demulsification and instability caused by the difference in solubility parameters between fluorinated groups and non-fluorinated groups, and the obtained fluoroacrylate nano-microspheres have excellent dielectric properties and hydrophobic and oleophobic properties, which can be used as fluorinated nano-materials and have very important significance in industries such as coatings, adhesives, textiles, and electronics.

[0009] One of the purposes of the present invention is to provide a synthesis method of fluoroacrylate organic nano-microspheres with high fluorine content, including the following steps:

[0010] (1) An emulsion polymerization is carried out with a raw material containing a fluorinated emulsifier and a fluorinated acrylate monomer to obtain a fluorinated acrylate emulsion;

[0011] (2) The fluorinated acrylate emulsion is demulsified, separated, dried and ground to obtain fluorinated acrylate organic nanospheres with a high fluorine content; the structural formula of the fluorinated emulsifier is:

[0012]

[0013] wherein, n1 = 1 - 5, n2 = 10 - 30, n3 = 10 - 30, n4 = 10 - 30.

[0014] Optionally, the raw material further includes a non-fluorinated acrylate monomer, an initiator, deionized water and a basic pH regulator.

[0015] Optionally, the fluorinated acrylate monomer is an acrylate containing fluorine atoms, preferably one or a combination of trifluoroethyl methacrylate, trifluoroethyl acrylate, tetrafluoropropyl methacrylate, tetrafluoropropyl acrylate, hexafluorobutyl methacrylate, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, perfluorooctylethyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, tridecafluorooctyl methacrylate, perfluorooctylethyl acrylate and 1,6-hexanediol dimethacrylate.

[0016] Optionally, the non-fluorinated acrylate monomer is one or a combination of methyl methacrylate, methyl acrylate, butyl methacrylate, butyl acrylate, n-pentyl methacrylate, n-pentyl acrylate, isopentyl methacrylate, isopentyl acrylate, n-hexyl methacrylate, n-hexyl acrylate, cyclohexyl acrylate, n-heptyl methacrylate, n-heptyl acrylate, n-octyl methacrylate, n-octyl acrylate, isooctyl methacrylate, isooctyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, n-nonyl methacrylate, n-nonyl acrylate, isononyl methacrylate, isononyl acrylate, n-decyl methacrylate, n-decyl acrylate, isodecyl methacrylate, isodecyl acrylate, n-dodecyl methacrylate, n-dodecyl acrylate, isomyristyl methacrylate, isomyristyl acrylate, n-tridecyl methacrylate, n-tridecyl acrylate, n-tetradecyl methacrylate, n-tetradecyl acrylate, n-stearyl methacrylate, n-stearyl acrylate, isostearyl methacrylate, isostearyl acrylate, n-lauryl methacrylate, n-lauryl acrylate.

[0017] Optionally, the initiator is one or a combination of potassium persulfate, ammonium persulfate, sodium persulfate, benzoyl peroxide, lauroyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, azobisisobutyronitrile, azobisisoheptonitrile, azoisobutyronitrile formamide, and azobisisobutyramidine hydrochloride.

[0018] Optionally, the basic pH regulator is an organic base or an inorganic base; preferably, the inorganic base is one or a combination of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, and ammonia water.

[0019] Optionally, the previous step of the emulsion polymerization further includes mixing a fluorinated acrylate monomer and a non-fluorinated acrylate monomer to obtain a mixed monomer; and / or, preparing a seed emulsion.

[0020] Optionally, the mass ratio of the mixed monomer added in batches in the preparation of the seed emulsion and the emulsion polymerization step is 1:(2 - 4); and / or, the reaction temperature of the emulsion polymerization is 70 - 100 °C, and the reaction time is 30 - 180 min.

[0021] Optionally, the mass ratio of the fluorinated acrylate monomer to the non-fluorinated acrylate monomer is 1:(2 - 10); preferably 1:(2.4 - 10).

[0022] Optionally, step (2) is to add a certain amount of methanol to the fluorinated acrylate emulsion for demulsification. After the emulsion and the polymer powder are separated by stratification, filtration is carried out. The powder obtained after filtration is dried in an oven at 30 - 70 °C for 10 - 48 h to obtain fluorinated acrylate organic nanospheres with a high fluorine content.

[0023] Optionally, the raw materials further include a co-emulsifier and an emulsifier for compounding, and the co-emulsifier is ammonium perfluorooctanoate.

[0024] Optionally, the mass ratio of deionized water, mixed monomer, emulsifier, basic pH regulator, and initiator is 100:(0.2 - 1):(0.05 - 0.2):(0.01 - 0.05):(0.001 - 0.005).

[0025] The second object of the present invention is to provide fluorinated acrylate organic nanospheres with a high fluorine content prepared by the method as described above.

[0026] Optionally, the content of the fluorinated monomer is 70 wt% or more, and the content of fluorine atoms is more than 40 wt%.

[0027] The third object of the present invention is to provide an application of the fluorinated acrylate organic nanospheres with a high fluorine content as described above, which can be used in the coatings, adhesives, textiles, wire and cable, anti-corrosion, automotive, machinery, electrical, aerospace, and electronics industries.

[0028] A fourth object of the present invention is to provide an application of the fluorinated acrylate organic nanospheres with a high fluorine content as described above, which can be used as a filler to improve the hydrophobic, oleophobic and low dielectric properties of polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of emulsion polymerization for Examples 1-7.

[0030] Figure 2 It is an infrared spectrum diagram of the fluorinated emulsifier for Examples 1-7.

[0031] Figure 3 It is a hydrophobic and oleophobic diagram of the fluorinated acrylate organic nanospheres with a high fluorine content for Examples 1-7.

[0032] Figure 4 It is a SEM scanning electron microscope diagram of the fluorinated acrylate organic nanospheres with a high fluorine content for Example 7.

[0033] Figure 5 It is a particle size distribution diagram of the fluorinated acrylate organic nanospheres with a high fluorine content for Examples 1-7.

[0034] Figure 6 It is a dielectric data diagram of the fluorinated acrylate organic nanospheres with a high fluorine content for Examples 1-7. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is given.

[0036] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0037] The preparation method of the fluorinated acrylate nanoparticles of the present invention is specifically described below by way of examples. The main raw materials and equipment used: Unless otherwise specified, the raw materials and equipment in each example and comparative example are the same; the materials without specifying the specific model or type are from the common same model purchased from the market and are not specifically limited.

[0038] Example 1

[0039] (1) Synthesis of the fluorinated emulsifier: The structure of the emulsifier is the following structure:

[0040]

[0041] Among them, n1 = 3, n2 = 22;

[0042] (2) Preparation of mixed monomers: Mix 23 wt% methyl methacrylate, 30 wt% butyl methacrylate, 37 wt% 2-(perfluorooctyl)ethyl methacrylate, and 10 wt% 1,6-hexanediol dimethacrylate evenly to obtain mixed monomers;

[0043] (3) Preparation of seed emulsion: In a beaker, load deionized water at 300 wt% of the mixed monomers, 1 / 4 of the mixed monomers, an emulsifier at 4 wt% of the mixed monomers (the emulsifier is a compound of ammonium perfluorooctanoate and fluorinated emulsifier with a mass ratio of 3:7), and NaHCO3 powder at 1 wt% of the mixed monomers, then ultrasonic for 10 min. After forming a homogeneous solution, stir and emulsify at a speed of 10000 rpm for 20 min. When a uniform emulsion is formed, pour the emulsion into a reactor equipped with a stirrer, a condenser, and a feeding device, and then add an initiator at 0.120 wt% of the mixed monomers. React at room temperature for 20 min to obtain a seed emulsion;

[0044] (4) Preparation of fluorinated acrylate emulsion: Simultaneously dropwise add an aqueous initiator solution at 0.169 wt% (the concentration of the aqueous initiator solution is 0.42 wt%) and the remaining 3 / 4 of the mixed monomers to the seed emulsion. After the dropping is completed, keep warm at 80 °C for 90 min to obtain a fluorinated acrylate emulsion.

[0045] (5) Preparation of fluorinated acrylate organic nanospheres: Add methanol at 500 wt% of the monomer content to the fluorinated acrylate emulsion for demulsification. After the emulsion and polymer powder are separated and precipitated, perform suction filtration. The powder obtained after suction filtration is dried in an oven at 50 °C for 24 h to obtain fluorinated acrylate organic nanospheres with a high fluorine content.

[0046] Example 2

[0047] Except for the preparation of the mixed monomers in step (2): Mix 23 wt% methyl methacrylate, 23 wt% butyl methacrylate, 44 wt% 2-(perfluorooctyl)ethyl methacrylate, and 10 wt% 1,6-hexanediol dimethacrylate evenly, the others are the same as in Example 1.

[0048] Example 3

[0049] Except for the preparation of the mixed monomers in step (2): Mix 15 wt% methyl methacrylate, 15 wt% butyl methacrylate, 60 wt% 2-(perfluorooctyl)ethyl methacrylate, and 10 wt% 1,6-hexanediol dimethacrylate evenly, the others are the same as in Example 1.

[0050] Example 4

[0051] Preparation of the mixed monomers in step (2): 10 wt% methyl methacrylate, 10 wt% butyl methacrylate, 70 wt% 2-(perfluorooctyl)ethyl methacrylate, and 10 wt% 1,6-hexanediol dimethacrylate were mixed evenly. Otherwise, it was the same as in Example 1.

[0052] Example 5

[0053] Preparation of the mixed monomers in step (2): 5 wt% methyl methacrylate, 5 wt% butyl methacrylate, 80 wt% 2-(perfluorooctyl)ethyl methacrylate, and 10 wt% 1,6-hexanediol dimethacrylate were mixed evenly. Otherwise, it was the same as in Example 1.

[0054] Example 6

[0055] Preparation of the mixed monomers in step (2): 5 wt% methyl methacrylate, 70 wt% 2-(perfluorooctyl)ethyl methacrylate, 10 wt% hexafluorobutyl methacrylate, and 15 wt% 1,6-hexanediol dimethacrylate were mixed evenly. Otherwise, it was the same as in Example 1.

[0056] Example 7

[0057] Preparation of the mixed monomers in step (2): 15 wt% butyl methacrylate, 70 wt% 2-(perfluorooctyl)ethyl methacrylate, 10 wt% hexafluorobutyl methacrylate, and 5 wt% 1,6-hexanediol dimethacrylate were mixed evenly. Otherwise, it was the same as in Example 1.

[0058] Performance testing

[0059] 1. Fourier transform infrared spectrometer (FTIR): Using a Nicolet Nexus 670 spectrometer, the KBr pellet method was adopted, and the wavenumber range of the infrared spectrum was 500 - 3500 cm -1 , and the resolution was 4 cm -1 .

[0060] 2. Static contact angle test: The static water contact angle of the epoxy resin surface was measured using a Drop Shape Analysis System DSA10 - MK2 (Kruess, Germany).

[0061] 3. Scanning electron microscope (SEM): The surface of the specimen was sputter-coated with gold and observed using a scanning electron microscope (SEM, Hitachi Limited, S - 7800) at an acceleration voltage of 10 kV.

[0062] 4. Dielectric property test: At 25 °C, 10 4- 10 7In the Hz frequency range, the dielectric properties of the fluorinated acrylate were measured using a precision impedance analyzer (Agilent 4294A).

[0063] 5. Particle size distribution: The particle size and diameter distribution of the latex particles were measured using a dynamic light scattering (DLS) nanoparticle size analyzer ((Malvern ZEN1690, Malvern, U.K)).

[0064] The specific test data are shown in the figure, as Figure 2 shown. For the fluorinated emulsifier of the present invention, the infrared peak at 3510 cm -1 represents -OH in the emulsifier, and the infrared peak at 1210 cm -1 represents -CF. From Figure 3 it can be seen that the prepared fluorinated acrylate with a high fluorine content has good hydrophobic and lipophobic properties towards water and butanediol. The water contact angle in Example 7 can reach 152°, and as the fluorine element content increases, the water contact angle increases. From Figure 4 and Figure 5 it can be seen that the organic nanospheres of the fluorinated acrylate with a high fluorine content prepared by the present invention are regular spherical in shape, and the particle size distribution is between 100 and 250 nm. The microspheres in this nanoscale particle size range are conducive to forming a dense coating, reducing defects, and enhancing the waterproof and anti-fouling properties; for resin modification, the nanoscale microspheres have a large specific surface area, which is beneficial to enhancing the strong interaction force and stable interfacial bonding with the resin. From Figure 6 it can be seen that as the fluorine element content increases, the dielectric constant decreases. The dielectric constant in Example 5 is the lowest and can reach 2.416 at 10 7 Hz.

[0065] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration purposes and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for synthesizing fluorinated acrylate organic nano - microspheres with a high fluorine content, characterized in that, It includes the following steps: (1) Emulsion polymerization is carried out with a raw material containing a fluorinated emulsifier and a fluorinated acrylate monomer to obtain a fluorinated acrylate emulsion; (2) The fluorinated acrylate emulsion is demulsified, separated, dried and ground to obtain fluorinated acrylate organic nano-microspheres with a high fluorine content; the structural formula of the fluorinated emulsifier is: wherein, n1 = 1 - 5, n2 = 10 - 30, n3 = 10 - 30, n4 = 10 - 30.

2. The synthesis method of the fluorinated acrylate organic nanospheres with a high fluorine content according to claim 1, wherein, The raw material also contains a non-fluorinated acrylate monomer, an initiator, deionized water and a basic pH regulator.

3. The synthesis method of the fluorinated acrylate organic nanospheres with a high fluorine content according to claim 1 or 2, characterized in that, The fluorinated acrylate monomer is one or a combination of trifluoroethyl methacrylate, trifluoroethyl acrylate, tetrafluoropropyl methacrylate, tetrafluoropropyl acrylate, hexafluorobutyl methacrylate, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, perfluorooctylethyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, tridecafluorooctyl methacrylate, perfluorooctylethyl acrylate and 1,6-hexanediol dimethacrylate.

4. The synthesis method of the fluorinated acrylate organic nanospheres with a high fluorine content according to claim 2, characterized in that, The non-fluorinated acrylate monomer is one or a combination of methyl methacrylate, methyl acrylate, butyl methacrylate, butyl acrylate, n-pentyl methacrylate, n-pentyl acrylate, isopentyl methacrylate, isopentyl acrylate, n-hexyl methacrylate, n-hexyl acrylate, cyclohexyl acrylate, n-heptyl methacrylate, n-heptyl acrylate, n-octyl methacrylate, n-octyl acrylate, isooctyl methacrylate, isooctyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, n-nonyl methacrylate, n-nonyl acrylate, isononyl methacrylate, isononyl acrylate, n-decyl methacrylate, n-decyl acrylate, isodecyl methacrylate, isodecyl acrylate, n-dodecyl methacrylate, n-dodecyl acrylate, isomyristyl methacrylate, isomyristyl acrylate, n-tridecyl methacrylate, n-tridecyl acrylate, n-tetradecyl methacrylate, n-tetradecyl acrylate, n-stearyl methacrylate, n-stearyl acrylate, isostearyl methacrylate, isostearyl acrylate, n-lauryl methacrylate, n-lauryl acrylate; and / or, the initiator is one or a combination of potassium persulfate, ammonium persulfate, sodium persulfate, benzoyl peroxide, lauroyl peroxide, tert-butyl perbenzoate, diisopropyl peroxydicarbonate, azobisisobutyronitrile, azobisisoheptonitrile, azoisobutyronitrile formamide, azobis(2-methylpropionamidine) dihydrochloride; and / or, the basic pH regulator is an organic base or an inorganic base; preferably, the inorganic base is one or a combination of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate and ammonia water.

5. The synthesis method of the fluorinated acrylate organic nano-microspheres with a high fluorine content according to claim 2, wherein, The previous steps of the emulsion polymerization also include mixing the fluorinated acrylate monomer and the non-fluorinated acrylate monomer to obtain a mixed monomer; and / or, preparing a seed emulsion.

6. The synthesis method of the fluorinated acrylate organic nano-microspheres with a high fluorine content according to claim 2, wherein, The mass ratio of the fluorinated acrylate monomer to the non-fluorinated acrylate monomer is 1:(2 - 10).

7. The synthesis method of the fluorinated acrylate organic nanospheres with a high fluorine content according to claim 1 or 2, characterized in that, The raw materials further include a co-emulsifier compounded with an emulsifier, and the co-emulsifier is ammonium perfluorooctanoate.

8. A fluorine-containing acrylate organic nanosphere with a high fluorine content prepared by the method according to any one of claims 1-7.

9. The fluorinated acrylate organic nano microspheres with a high fluorine content according to claim 8, characterized in that, The content of the fluorine-containing monomer is 70 wt% or more, and the content of fluorine atoms is more than 40 wt%.

10. The application of the fluorinated acrylate organic nanospheres with a high fluorine content as described in claim 8 or 9, characterized in that, It can be used in the coatings, adhesives, textile, wire and cable, anti-corrosion, automotive, machinery, electrical, aerospace and electronics industries.

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