Preparation method of bifunctional modified silicone oil and preparation method of epoxy composite coating of bifunctional modified silicone oil

Abstract

The invention relates to the technical field of preparation of composite coatings, in particular to bifunctional modified silicone oil and a preparation method of an epoxy composite coating of the bifunctional modified silicone oil. The preparation method specifically comprises the following steps: S1, under the protection of nitrogen, adding hydrogen-containing silicone oil, a fluorine-containing acrylate monomer, allyl glycidyl ether (AGE), chloroplatinic acid, a polymerization inhibitor and a solvent into a flask, and preparing fluorine-containing epoxy bifunctional modified silicone oil through a one-pot method; and S2, uniformly mixing epoxy resin, the bifunctional modified silicone oil prepared in the S1, fumed silica and an epoxy resin curing agent, and standing to obtain the modified composite coating. The coating prepared by the invention has hydrophobic and oleophobic double antifouling effects, meanwhile, the adhesive force is remarkably enhanced, and the problem that the epoxy coating is easy to embrittle at low temperature can be solved.

Description

Technical Field

[0001] This invention relates to the field of composite coating preparation technology, specifically to a method for preparing a bifunctional modified silicone oil and its epoxy composite coating. Background Technology

[0002] Epoxy resin coatings are commonly used coatings, but they have disadvantages such as high surface energy, easy contamination; poor toughness, easy brittleness at low temperatures; poor weather resistance, and easy yellowing and aging.

[0003] Ordinary silicone oil has a single function, possessing certain hydrophobicity but poor oleophobicity. Introducing fluorinated groups can further reduce surface energy and improve the hydrophobic and oleophobic properties of polymers. However, fluorinated silicone oil has poor interfacial compatibility with epoxy resin, and phase separation and oil floating phenomena are prone to occur during bonding.

[0004] Patent CN100371387C provides a method for preparing epoxy resin modified with epoxide silicone oil, but it only uses a single epoxide silicone oil (the side chain contains only epoxy groups), and can only crosslink with epoxy matrix through epoxy ring opening. It does not have low surface energy fluorine-containing groups and interface compatibility control design, so it cannot reduce the surface energy of the coating, improve hydrophobic and oleophobic properties and aging resistance, and can only improve mechanical properties. Summary of the Invention

[0005] This invention provides a method for synthesizing a bifunctional modified silicone oil and a method for preparing an epoxy composite coating.

[0006] The present invention adopts the following technical solution:

[0007] The synthesis method of bifunctional modified silicone oil is as follows: under nitrogen protection, hydrogen-containing silicone oil, fluorinated acrylate monomers, allyl glycidyl ether (AGE), chloroplatinic acid, polymerization inhibitor and solvent are added to a flask and prepared by one-pot method to obtain fluorinated epoxy bifunctional modified silicone oil.

[0008] Further, the specific synthesis method of the modified silicone oil is as follows: Hydrogen-containing silicone oil (hydrogen content selected as 0.8%) is weighed and added to a three-necked flask equipped with a mechanical stirrer. Under a vacuum of 50 mmHg, the temperature is raised to 110°C and dehydrated for 1 hour. The dehydrated hydrogen-containing silicone oil, fluorinated acrylate monomers, allyl glycidyl ether (AGE), polymerization inhibitor, chloroplatinic acid, and solvent are added to the flask. The temperature is raised to 130°C and maintained for 3-4 hours. After the reaction is completed, the temperature is lowered to 80°C, and unreacted small molecule monomers and solvents are removed by vacuum distillation under a vacuum of 50 mmHg. After removal is complete, the temperature is lowered to 50°C and the product is discharged.

[0009] The fluorinated acrylate monomer is one of trifluoroethyl methacrylate, trifluoroethyl acrylate, or hexafluorobutyl acrylate; the polymerization inhibitor is phenothiazine (PTZ) or p-hydroxyanisole (MEHQ); and the solvent is toluene, xylene, or a mixture thereof.

[0010] The molar ratio of Si-H bonds in the hydrogen-containing silicone oil to C=C bonds in monomers containing double bonds (fluorinated acrylate monomers, allyl glycidyl ether) is 1:(1.05-1.1), and the molar ratio of fluorinated acrylate monomers to allyl glycidyl ether is 0:1-2:1 (preferably 1:1).

[0011] The amount of polymerization inhibitor (based on the mass fraction of fluorinated acrylate monomer) is 0.1%-0.2%, the amount of solvent (based on the mass fraction of hydrogen-containing silicone oil) is 20%-30%, and the amount of chloroplatinic acid (based on the total mass of the reaction system) is 20-30 ppm.

[0012] The preparation method of epoxy composite coating is as follows: epoxy resin, the above-prepared bifunctional modified silicone oil, fumed silica, and epoxy resin curing agent are mixed evenly, and after standing, the slurry is evenly applied to the substrate surface to be coated by brushing or spraying. Then, it is cured according to the process of 80℃ / 3h+150℃ / 2h to obtain epoxy composite coating with high anti-fouling and strong adhesion.

[0013] Furthermore, the specific preparation method of the composite coating is as follows: Epoxy resin is weighed and added to a flask equipped with a mechanical stirrer, the temperature is raised to 50-60℃, fumed silica and modified silicone oil are slowly added, the stirring speed is maintained at 600-700 r / min, and the stirring is carried out for 20-30 min; after stirring evenly, the temperature is lowered to 20-25℃, the stirring speed is reduced to 200-300 r / min, epoxy resin curing agent is added, and the mixture is stirred at low speed for 5-10 min. The slurry is evenly applied to the substrate surface to be coated by brushing or spraying, and then cured according to the process of 80℃ / 3h + 150℃ / 2h to obtain an epoxy composite coating with both high anti-fouling and strong adhesion.

[0014] The epoxy resin is one or more of bisphenol A (E-51) or bisphenol F (E-50), the fumed silica is Wacker HDKH20 hydrophobic silica, and the epoxy resin curing agent is one or more of isophorone diamine (IPDA) and m-xylene diamine (MXDA).

[0015] The composite coating comprises the following parts by weight: epoxy resin (100 parts), modified silicone oil (5-9 parts), fumed silica (3-5 parts), and curing agent (15-19 parts).

[0016] Beneficial effects:

[0017] The fluorine groups in the modified silicone oil molecules have extremely low surface energy and spontaneously migrate to the surface during coating curing. Simultaneously, hydrophobic fumed silica nanoparticles construct a micro-nano rough structure on the coating surface, with both contributing to a synergistic hydrophobic and oleophobic effect. Furthermore, the epoxy groups on the modified silicone oil side chains chemically bond with the epoxy resin, rather than through physical blending, ensuring the fluorine groups are stably "anchored" to the coating surface, significantly enhancing adhesion and preventing migration and loss due to long-term use or rain erosion. The Si-O-Si flexible backbone of the modified silicone oil is uniformly dispersed within the epoxy crosslinking network, providing internal toughening. Additionally, the UV resistance of the Si-O bonds is far superior to that of the C-C bonds, offering dual protection and delaying coating aging. The co-curing reaction of the side-chain epoxy groups prevents phase separation and eliminates interfacial defects.

[0018] This invention utilizes a modified coating prepared by combining fluorinated epoxy bifunctional modified silicone oil with epoxy resin and fumed silica. This coating can simultaneously achieve the characteristics of high hydrophobicity and oleophobicity, strong adhesion, and excellent weather resistance, solving the problems of traditional epoxy coatings such as easy contamination, easy brittleness at low temperatures, and poor weather resistance. At the same time, it overcomes the defects of poor compatibility between pure fluorinated silicone oil and epoxy resin and easy performance degradation. Attached Figure Description

[0019] Figure 1 The infrared spectrum of the epoxy fluorine-containing co-modified silicone oil prepared in Example 1. Detailed Implementation

[0020] The technical solutions of the present invention will be further explained below with reference to embodiments, and the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specifically stated, the numerical values ​​set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. Furthermore, the expression "within a range" is generally considered to exclude endpoint values.

[0022] Experimental methods in the following examples that do not specify specific conditions are generally performed according to national standards; if no corresponding national standard exists, they are performed according to general standard requirements or general methods.

[0023] Example 1

[0024] S1. Weigh 100 parts by weight of hydrogen-containing silicone oil (hydrogen content selected as 0.8%) and add it to a three-necked flask equipped with a mechanical stirrer. Under a vacuum of 50 mmHg, heat to 110°C and remove water by vacuum for 1 hour. After water removal, add 76.44 parts by weight of trifluoroethyl methacrylate, 47.88 parts by weight of allyl glycidyl ether, 20 parts by weight of toluene solvent, 0.1 parts by weight of phenothiazine, and 20 ppm (based on the total mass of the reaction system) of chloroplatinic acid in sequence. Heat to 130°C and maintain the temperature for 3 hours. After the reaction is completed, cool down to 80°C and remove unreacted small molecule monomers and solvents by vacuum distillation under a vacuum of 50 mmHg. After removal is complete, cool down to 50°C and discharge the material.

[0025] S2. Weigh 100 parts by weight of bisphenol A (E-51) type epoxy resin and add it to a flask equipped with a mechanical stirrer. Heat the flask to 55°C, add 3 parts of fumed silica and 5 parts of modified silicone oil, and maintain the stirring speed at 600 r / min for 20 min. After stirring evenly, cool the flask to 20°C, reduce the stirring speed to 200 r / min, add 15 parts of isophorone diamine (IPDA), and stir at low speed for 5 min. Apply the slurry evenly to the substrate surface to be coated using a brushing method, and then cure it according to the process of 80°C / 3h + 150°C / 2h to obtain an epoxy composite coating with high anti-fouling and strong adhesion.

[0026] like Figure 1 The image shows the infrared spectrum of the prepared epoxy-fluorinated co-modified silicone oil in the 1000-1100 cm⁻¹ range. -1 The strong peak at 1200-1280 cm⁻¹ corresponds to the characteristic Si-O-Si peak in modified silicone oil. -1 The characteristic peak at 900-950 cm⁻¹ corresponds to the vibrational coupling absorption peak of the CF bond on the side group of the modified silicone oil, while the peak at 900-950 cm⁻¹ corresponds to the vibrational coupling absorption peak of the CF bond on the side group of the modified silicone oil. -1 The medium-intensity peak appearing at 2150 cm⁻¹ corresponds to the bending vibration of the COC bond in the epoxy ring on the side group, while the peak at 2150 cm⁻¹ corresponds to the bending vibration of the COC bond in the epoxy ring on the side group. -1 and 1700cm -1 The infrared characteristic peaks of the corresponding Si-H bonds and C=C bonds have basically disappeared, which indicates the successful synthesis of the modified silicone oil.

[0027] Example 2

[0028] In Example 1S1, 76.44 parts by weight of trifluoroethyl methacrylate and 47.88 parts by weight of allyl glycidyl ether were replaced with 66.53 parts by weight of trifluoroethyl acrylate and 49.25 parts by weight of allyl glycidyl ether, while keeping other conditions unchanged. In S2, all conditions remained unchanged.

[0029] Example 3

[0030] In Example 1S1, 76.44 parts by weight of trifluoroethyl methacrylate and 47.88 parts by weight of allyl glycidyl ether were replaced with 108.2 parts by weight of hexafluorobutyl acrylate and 50.16 parts by weight of allyl glycidyl ether, while keeping other conditions unchanged. The conditions in S2 were also kept unchanged.

[0031] Example 4

[0032] In Example 1S1, the molar ratio of trifluoroethyl methacrylate to allyl glycidyl ether was changed from 1:1 to 2:1, while other conditions remained unchanged. In Example 2, all conditions remained unchanged.

[0033] Example 5

[0034] In Example 1S1, the molar ratio of trifluoroethyl methacrylate to allyl glycidyl ether was changed from 1:1 to 1:2, while other conditions remained unchanged. In Example 2, all conditions remained unchanged.

[0035] Example 6

[0036] S1. Weigh 100 parts by weight of hydrogen-containing silicone oil and add it to a three-necked flask equipped with a mechanical stirrer. Under a vacuum of 50 mmHg, heat to 110°C and remove water by vacuum for 1 hour. After water removal, add 66.53 parts by weight of trifluoroethyl acrylate, 49.25 parts by weight of allyl glycidyl ether, 25 parts by weight of xylene solvent, 0.12 parts by weight of p-hydroxyanisole, and 25 ppm (based on the total mass of the reaction system) of chloroplatinic acid in sequence. Heat to 130°C and maintain the temperature for 3.5 hours. After the reaction is completed, cool down to 80°C and remove unreacted small molecule monomers and solvents by vacuum distillation under a vacuum of 50 mmHg. After removal is complete, cool down to 50°C and discharge the material.

[0037] S2. Weigh 100 parts by weight of bisphenol F (E-50) type epoxy resin and add it to a flask equipped with a mechanical stirrer. Heat the flask to 55°C and slowly add 4 parts of fumed silica and 7 parts of modified silicone oil. Maintain the stirring speed at 650 r / min and stir for 25 min. After stirring evenly, cool the flask to 25°C and reduce the stirring speed to 250 r / min. Add 17 parts of m-xylenediamine (MXDA) and stir at low speed for 8 min. Apply the slurry evenly to the substrate surface to be coated using a spraying method. Then cure the slurry according to the process of 80°C / 3h + 150°C / 2h to obtain an epoxy composite coating with high anti-fouling and strong adhesion.

[0038] Example 7

[0039] S1. Weigh 100 parts by weight of hydrogen-containing silicone oil and add it to a three-necked flask equipped with a mechanical stirrer. Under a vacuum of 50 mmHg, heat to 110°C and remove water by vacuum for 1 hour. After water removal, add 108.2 parts by weight of hexafluorobutyl acrylate, 50.16 parts by weight of allyl glycidyl ether, 30 parts by weight of xylene solvent, 0.15 parts by weight of p-hydroxyanisole, and 30 ppm (based on the total mass of the reaction system) of chloroplatinic acid in sequence. Heat to 130°C and maintain the temperature for 4 hours. After the reaction is completed, cool down to 80°C and remove unreacted small molecule monomers and solvents by vacuum distillation under a vacuum of 50 mmHg. After removal is complete, cool down to 50°C and discharge the material.

[0040] S2. Weigh 100 parts by weight of bisphenol F (E-50) type epoxy resin and add it to a flask equipped with a mechanical stirrer. Heat the flask to 55°C and slowly add 5 parts of fumed silica and 9 parts of modified silicone oil. Maintain the stirring speed at 700 r / min and stir for 30 min. After stirring evenly, cool the flask to 25°C and reduce the stirring speed to 300 r / min. Add 19 parts of m-xylenediamine (MXDA) and stir at low speed for 10 min. Apply the slurry evenly to the substrate surface using a brushing method. Then cure the slurry according to the process of 80°C / 3h + 150°C / 2h to obtain an epoxy composite coating with high anti-fouling properties and strong adhesion.

[0041] Example 8

[0042] The mass fraction of modified silicone oil in S2 of Example 1 is changed to 2 parts, while other conditions remain unchanged, and all conditions in S1 remain unchanged.

[0043] Example 9

[0044] The mass fraction of modified silicone oil in S2 of Example 1 was changed to 12 parts, while other conditions remained unchanged, and all conditions in S1 remained unchanged.

[0045] Example 10

[0046] In Example 1, the mass fraction of fumed silica in S2 is changed to 1 part, while other conditions remain unchanged, and all conditions in S1 remain unchanged.

[0047] Example 11

[0048] The mass fraction of fumed silica in S2 of Example 1 was changed to 8 parts, while other conditions remained unchanged, and all conditions in S1 remained unchanged.

[0049] Comparative Example 1

[0050] Weigh 100 parts by weight of bisphenol A (E-51) type epoxy resin and add it to a flask equipped with a mechanical stirrer. Heat the flask to 55°C and slowly add 3 parts of fumed silica and 5 parts of hydrogen-containing silicone oil with a hydrogen content of 0.8%. Maintain the stirring speed at 600 r / min and stir for 20 min. After stirring evenly, cool the flask to 20°C and reduce the stirring speed to 200 r / min. Add 15 parts of isophorone diamine (IPDA) and stir at low speed for 5 min. Apply the slurry evenly to the substrate surface to be coated using a brushing method. Then cure the slurry according to the process of 80°C / 3h + 150°C / 2h to obtain an epoxy composite coating with high antifouling properties and strong adhesion.

[0051] Comparative Example 2

[0052] Weigh 100 parts by weight of bisphenol A (E-51) type epoxy resin and add it to a flask equipped with a mechanical stirrer. Add 15 parts of isophorone diamine (IPDA) and stir at a low speed of 200 r / min for 5 min at 20°C to obtain the epoxy resin coating.

[0053] Comparative Example 3

[0054] In Example 1, allyl glycidyl ether was not added in S1, and all other conditions remained the same. In S2, all conditions remained the same.

[0055] Comparative Example 4

[0056] In Example 1, trifluoroethyl methacrylate was not added in S1, and all other conditions remained the same. In S2, all conditions remained the same.

[0057] Comparative Example 5

[0058] In Example 1, the mass fraction of fumed silica in S2 is changed to 0 parts, while other conditions remain unchanged, and all conditions in S1 remain unchanged.

[0059] Comparative Example 6

[0060] In Example 1, trifluoroethyl methacrylate in S1 was replaced with methyl methacrylate, while other conditions remained unchanged, and all conditions in S2 remained unchanged.

[0061] Test method:

[0062] (1) Adhesion test: GB / T 9286-1998 Cross-cut test;

[0063] (2) Hydrophobicity test: Static water contact angle 2μL deionized water: GB / T 30693-2014 Measurement of contact angle of plastic films and sheets;

[0064] (3) Oleophobicity test: Static contact angle method (2 μL n-hexadecane);

[0065] (3) UV aging test: GB / T14522-2008 "Artificial climate aging test method for plastics, coatings and rubber materials for mechanical industry products", UV aging time 1000h.

[0066] Table 1 Test data for each embodiment

[0067] Adhesion Hydrophobic angle Oil-repellent angle UV aging resistance (yellowing index ΔYI) Example 1 5B level 123° 103° 2.6 Example 2 5B level 127° 109° 2.7 Example 3 5B level 126° 106° 2.6 Example 4 4B level 131° 112° 2.4 Example 5 5B level 111° 82° 3.6 Example 6 5B level 127° 109° 2.7 Example 7 5B level 126° 106° 2.6 Example 8 3B level 83° 68° 11.2 Example 9 4B level 55° 37° 17.6 Example 10 5B level 107° 83° 4.2 Example 11 2B level 136° 113° 2.7 Comparative Example 1 5B level 110° 85° 4.9 Comparative Example 2 2B level 116° 87° 3.7 Comparative Example 3 1B level 138° 116° 1.6 Comparative Example 4 5B level 82° 55° 9.6 Comparative Example 5 5B level 105° 78° 6.3 Comparative Example 6 4B level 85° 58° 9.3

[0068] Table 1 shows that the composite coating with modified silicone oil exhibits significantly improved performance compared to the unmodified ordinary silicone oil coating and the pure epoxy resin coating. When the molar ratio of fluorinated groups to epoxy groups is 1:1 and it is combined with fumed silica, the coating achieves the best overall performance, balancing adhesion, hydrophobicity, oleophobicity, and resistance to UV yellowing. Excessive fluorinated groups enhance hydrophobicity and oleophobicity but weaken adhesion, thus diminishing its practical application value. With no fluorine or excessive epoxy groups, adhesion remains stable, but hydrophobicity, oleophobicity, and weather resistance are significantly degraded. Removing fumed silica significantly reduces the coating's hydrophobicity, oleophobicity, and weather resistance. Insufficient modified silicone oil results in insufficient fluorinated groups and flexible segments, significantly reducing hydrophobicity, oleophobicity, and low-temperature toughness. Excessive addition exceeds the compatibility threshold with epoxy resin, causing phase separation, leading to deterioration in adhesion and impact strength, increased construction defects, and only a slight improvement in hydrophobicity and oleophobicity before saturation. Insufficient addition of fumed silica prevents the formation of a continuous micro-nano rough structure, weakening the synergistic hydrophobic effect, reinforcing and thixotropic properties, and deteriorating aging resistance and workability. Excessive addition leads to particle agglomeration, destroying the cross-linking network, resulting in decreased adhesion and mechanical properties, and a deterioration in coating appearance and workability. In practical applications, the ratio of fluorinated / epoxy monomers can be fine-tuned according to the core requirements of the scenario (such as building exteriors, chemical equipment, and appliance casings) to adapt to different scenario needs.

[0069] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A bifunctional modified silicone oil, characterized in that: The bifunctional modified silicone oil is prepared by a one-pot method using hydrogen-containing silicone oil, fluorinated acrylate monomers, allyl glycidyl ether (AGE), chloroplatinic acid, polymerization inhibitor, and solvent.

2. The bifunctional modified silicone oil as described in claim 1, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 0.

8. Before use, it should be vacuum dehydrated at 110℃ and atmospheric pressure of 50 mmHg for 1-2 hours.

3. The bifunctional modified silicone oil as described in claim 1, characterized in that, The fluorinated acrylate monomer is one of trifluoroethyl methacrylate, trifluoroethyl acrylate, or hexafluorobutyl acrylate.

4. The bifunctional modified silicone oil as described in claim 1, characterized in that, The polymerization inhibitor is phenothiazine PTZ or p-hydroxyanisole MEHQ; the solvent is toluene, xylene or a mixture thereof.

5. The bifunctional modified silicone oil as described in claim 1, characterized in that, The molar ratio of Si-H bonds in hydrogen-containing silicone oil to the total C=C bonds in fluorinated acrylate monomers and allyl glycidyl ethers is 1: 1.05-1.1, the molar ratio of fluorinated acrylate monomers to allyl glycidyl ether is 0:1-2:

1.

6. The bifunctional modified silicone oil as described in claim 1, characterized in that, Chloroplatinic acid accounts for 20-30 ppm of the total mass of the reaction system; the amount of polymerization inhibitor is 0.1%-0.2% of the mass of fluorinated acrylate monomer; and the amount of solvent is 20%-30% of the mass of hydrogen-containing silicone oil.

7. A method for preparing an epoxy composite coating, characterized in that, The composite coating is prepared by mixing epoxy resin, the bifunctional modified silicone oil as described in claim 1, fumed silica and epoxy resin curing agent evenly, and applying the slurry evenly to the substrate surface by brushing or spraying, and then curing it according to the process of 80℃ / 3h+150℃ / 2h, thus obtaining an epoxy composite coating with high anti-fouling and strong adhesion.

8. The method for preparing the epoxy composite coating as described in claim 7, characterized in that, Composite coating according to parts by weight Composition: 100 parts epoxy resin, 5-9 parts bifunctional modified silicone oil, 3-5 parts fumed silica, and 15-19 parts epoxy resin curing agent.

9. The method for preparing the epoxy composite coating as described in claim 7, characterized in that, The epoxy resin is one or more of bisphenol A E-51 or bisphenol F E-50, the fumed silica is Wacker HDKH20 hydrophobic silica, and the epoxy resin curing agent is one or more of isophorone diamine and m-xylene diamine.

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