A hydrophobic protective glue and a preparation method thereof

Abstract

The application relates to a hydrophobic protective glue and a preparation method thereof, which comprises the following components in percentage by mass: 5-20 wt% of an MQ resin, 0.5-5 wt% of hydrophobic fumed silica, 1-4 wt% of composite silicone oil, and the balance of solvent oil. The composite silicone oil comprises epoxy-modified silicone oil and polyurethane-modified silicone oil. The hydrophobic protective glue forms a micro-nano rough structure after coating and curing. The hydrophobic protective glue is prepared by taking the MQ resin as the main body, combining the hydrophobic fumed silica, and further effectively improving the high-temperature resistance and water resistance through the composite silicone oil. The prepared protective glue has the properties of high-temperature resistance and hydrophobicity.

Description

TECHNICAL FIELD

[0001] The application relates to the field of protective glue, in particular to a hydrophobic protective glue and a preparation method thereof. BACKGROUND

[0002] An electronic circuit board is a basic component for carrying and connecting electronic components in an electronic device, and through a pre-designed conductive circuit, electrical connection between resistors, capacitors, chips, transistors and other components is realized, so that the electronic device can work normally according to the designed function; under the influence of the external environment of the metal solder joints, copper foil circuits and other precision parts on the circuit board, short circuit, electric leakage and corrosion may occur; the application of protective glue on the electronic circuit board is a key link for ensuring the reliability of the circuit board in the electronic manufacturing field, and the core function is to form a uniform and dense protective film on the surface of the circuit board to isolate harmful factors in the external environment, thereby prolonging the service life of the circuit board and improving its stability.

[0003] In the working process of the chip in the electronic circuit board, the power loss generated will be converted into heat energy, so the electronic circuit board often faces a high-temperature environment; under the long-term high-temperature environment, the glue body of the protective glue is easy to become brittle or crack, loses mechanical strength, the electronic components on the electronic circuit board are loose and fixed, vibration protection fails, which affects the working quality of the electronic circuit board, and electronic devices are highly sensitive to water, so the hydrophobicity requirement of the protective glue is high; the current protective glue cannot meet the high-temperature and hydrophobic protection requirements. SUMMARY

[0004] In order to further improve the high-temperature resistance and hydrophobicity of the protective glue, the application provides a hydrophobic protective glue and a preparation method thereof.

[0005] In a first aspect, the application provides a hydrophobic protective glue, which adopts the following technical scheme:

[0006] A hydrophobic protective glue, according to mass percentage, comprises the following components:

[0007] MQ resin 5-20wt%, hydrophobic fumed silica 0.5-5wt%, composite silicone oil 1-4wt%, and the balance is solvent oil; the composite silicone oil comprises epoxy modified silicone oil and polyurethane modified silicone oil; the hydrophobic protective glue forms a micro-nano rough structure after coating and curing.

[0008] Preferably, the MQ resin is 9-11wt%, and the hydrophobic fumed silica is 1-1.5wt%.

[0009] By adopting the above technical scheme, the MQ resin, i.e., MQ silicone resin, which is a polyorganosiloxane product, is used as the resin base material of the hydrophobic protective glue, and the rigid skeleton thereof has good hardness, and the Si-O bond has extremely high bond energy, so that the MQ resin has good high-temperature resistance and hydrophobicity; the hydrophobic fumed silica is further added to the system, the surface of the hydrophobic fumed silica is treated by silane, and the hydrophobic fumed silica has good dispersing performance and hydrophobicity and good compatibility with the silicone resin, so that the hydrophobic fumed silica is used as a reinforcing filler to effectively improve the mechanical strength of the whole system. The highly branched chain segments contained in the polyurethane modified silicone oil and the three-dimensional spherical structure of the MQ resin play a role in inhibiting the depolymerization of the siloxane chain at high temperatures, and the siloxane segments in the molecular chain have excellent thermal stability, so that the polyurethane structure provides good adhesion, high toughness, impact resistance, and strong weather resistance, and further strengthens the protection effect of the protective glue. The epoxy group in the epoxy modified silicone oil has high adhesion and high temperature resistance, and the epoxy modified silicone oil further provides the high-temperature protection effect of the protective glue. In addition, the inventors add the polyurethane modified silicone oil and the epoxy modified silicone oil as the composite silicone oil to the protective glue, and the protective glue has unexpectedly good high-temperature resistance and hydrophobicity, which may be due to the following reasons: on the one hand, the epoxy groups in the polyurethane modified silicone oil and the epoxy modified silicone oil further react to form a network structure during curing, and the highly branched macromolecular structure is combined to form a more complex network system, and the MQ resin and the hydrophobic fumed silica are embedded in the network structure to form effective dispersion and anchoring, which greatly improves the compactness of the glue layer and fully plays the characteristics of the high-temperature-resistant groups; on the other hand, the rigid chain segments in the epoxy modified silicone oil and the flexible chain segments in the polyurethane modified silicone oil have inherent incompatibility in thermodynamics, and after chemical grafting to improve the overall compatibility, controllable microphase separation occurs in the subsequent curing process, and a uniform micro-nano scale rough structure is spontaneously formed on the surface of the glue layer, which can effectively improve the overall hydrophobicity and durability of the system.

[0010] Preferably, the mass ratio of the epoxy modified silicone oil to the polyurethane modified silicone oil is 2-2.2:1.

[0011] Further preferably, the mass ratio of the epoxy modified silicone oil to the polyurethane modified silicone oil is 2.1:1.

[0012] Experiments show that the mass ratio of the epoxy modified silicone oil to the polyurethane modified silicone oil is 2-2.2:1, which can achieve better high-temperature resistance and hydrophobicity, and the mass ratio of 2.1:1 further optimizes the performance of the protective glue, indicating that the high-temperature-resistant and hydrophobic system based on the specific structure between the two achieves the optimal synergistic effect within the above range.

[0013] Preferably, the preparation method of the polyurethane modified silicone oil comprises:

[0014] The itaconic acid is mixed with dipentaerythritol to obtain a macromolecular condensation complex; the isophorone diisocyanate is reacted with diethanolamine to obtain a prepolymer, the hydroxyl silicone oil is added to the prepolymer to react, and finally the macromolecular condensation complex is added to obtain the polyurethane modified silicone oil.

[0015] Specifically, the polyurethane modified silicone oil is prepared by the following method:

[0016] The itaconic acid is mixed with dipentaerythritol, N-methyl pyrrolidone is added, stirring is performed to obtain a prepolymer, the product is cooled after warming, the product is added to xylene for centrifugal treatment, the supernatant is removed, the precipitated solid is separated and dried to obtain a macromolecular condensation complex; the isophorone diisocyanate is mixed with dimethylformamide to obtain a mixed solution, diethanolamine is mixed with dimethylformamide to obtain a diethanolamine solution, the diethanolamine solution is added to the mixed solution to react, the reaction is continued after warming, then the hydroxyl silicone oil is added to react, and finally the macromolecular condensation complex is added to end-cap to obtain the polyurethane modified silicone oil.

[0017] The inventor prepares the polyurethane modified silicone oil through a conventional synthesis mechanism. The carboxyl group of itaconic acid and the hydroxyl group of dipentaerythritol are subjected to condensation reaction to obtain a macromolecular condensation complex, the isophorone diisocyanate is reacted with diethanolamine to generate a prepolymer containing end-NCO, the hydroxyl group at the end of the molecular chain of the hydroxyl silicone oil is first reacted with the end-NCO of the prepolymer to realize chemical grafting of the polyurethane segment and the silicone segment, and finally the highly branched macromolecular condensation complex is added to end-cap, and the resin end is rich in functional groups, which can significantly improve the crosslinking density.

[0018] The polyurethane modified silicone oil prepared above takes the hydroxyl silicone oil as a key raw material, the siloxane segment hinders the penetration of water molecules, reduces the occurrence of cracking in high-temperature conditions, and simultaneously strengthens the compatibility of the polyurethane modified silicone oil and the main silicone oil, and fully plays the toughness and impact resistance of polyurethane.

[0019] As preferred, the mass ratio between the itaconic acid and the dipentaerythritol is (2.7-2.9):1.

[0020] By adopting the above technical solution, the mass ratio between the itaconic acid and the dipentaerythritol is preferably within the above range, which effectively improves the stability of the prepared macromolecular condensation complex, so that the polyurethane modified silicone oil prepared subsequently has better hydrophobic and temperature-resistant properties.

[0021] As preferred, the mass proportion of the macromolecular condensation complex added accounts for 9.5-10.5wt% of the total amount of the prepolymer and the hydroxyl silicone oil.

[0022] By adopting the technical scheme, the proportion of the macromolecular condensation compound is preferably within the range, so that a more stable polyurethane modified silicone oil can be prepared, the toughness is better, the defects are reduced, and a uniform microphase separation structure is beneficial to be formed.

[0023] Preferably, the preparation method of the epoxy modified silicone oil comprises:

[0024] 2,6-dichlorobenzonitrile, bisphenol A are reacted to obtain a polyarylether nitrile; the polyarylether nitrile is reacted with epichlorohydrin to obtain a modified epoxy resin; and the amino silicone oil and the modified epoxy resin are mixed and reacted to obtain the epoxy modified silicone oil.

[0025] Specifically, the epoxy modified silicone oil is prepared by the following method:

[0026] 2,6-dichlorobenzonitrile, bisphenol A and potassium carbonate are mixed, N-methyl pyrrolidone and toluene are added, dehydration treatment is performed, the mixture is warmed, and stirring reaction is performed to obtain a reaction product; the reaction product is washed to neutral, reflux purification is performed, and drying is performed to obtain a polyarylether nitrile; the polyarylether nitrile is mixed with epichlorohydrin, sodium hydroxide solution is added, warming reaction is performed, and after cooling, washing is performed, and solvent is removed by rotary evaporation to obtain a modified epoxy resin; the amino silicone oil, the modified epoxy resin and a solvent are mixed, warming stirring reaction is performed, and the epoxy modified silicone oil is obtained.

[0027] By adopting the technical scheme, the polyarylether nitrile chain is rich in stable arylether bonds, then the polyarylether nitrile is reacted with epichlorohydrin in a sodium hydroxide solution to introduce active epoxy groups into the molecular chain, at the same time, the rigid aromatic ring and the cyano structure of the polyarylether nitrile are completely retained, so that the modified epoxy resin still has excellent high-temperature resistance and chemical resistance, after the introduction of the amino silicone oil, partial ring-opening addition reaction of the epoxy groups occurs, the epoxy modified silicone oil is formed, the overall system can play a synergistic high-temperature resistance role, the hydrophobicity is also improved, the rigid aromatic ring of the polyarylether nitrile and the flexible combination of the siloxane chain segment play a good stability, and the impact resistance is improved.

[0028] The polyurethane modified silicone oil and the epoxy modified silicone oil prepared by the process are used as composite silicone oil, the high-temperature resistance and water resistance of the protective glue are greatly improved by a small amount of addition.

[0029] Specifically, the polyurethane modified silicone oil and the epoxy modified silicone oil form a crosslinked network, have a synergistic effect of enhancing mechanical strength and moisture and heat resistance, and at the same time, play a synergistic role in reducing the cracking phenomenon caused by high temperature or water absorption, further improving the heat and water resistance of the protective glue. The active groups in the high-branched macromolecular structure contained in the polyurethane modified silicone oil can further crosslink with the epoxy groups in the epoxy modified silicone oil to form a network structure during curing, thereby strengthening the compactness, and the rigid groups in the modified epoxy segment are grafted on the high-branched molecular segment through crosslinking, coordinating the tough and rigid structure phase separation area, and the modification of both based on silicone oil maintains a certain system compatibility, which is beneficial to improving the flexibility and strength of the glue while forming a controllable micro phase separation and strengthening the stable structure of this micro-nano roughness, which is beneficial to forming a glue layer with hydrophobicity and compactness, and synergistically improving the high temperature resistance and hydrophobicity.

[0030] Preferably, the composite silicone oil is prepared by the following method:

[0031] The epoxy modified silicone oil and the polyurethane modified silicone oil are uniformly mixed to obtain the composite silicone oil.

[0032] By adopting the above technical scheme, the epoxy modified silicone oil and the polyurethane modified silicone oil are premixed to form the composite silicone oil, which simplifies the process, forms a sufficient dispersion, and ensures that the protective glue has good water resistance and temperature resistance.

[0033] In a second aspect, the application provides a preparation method of a hydrophobic protective glue, which adopts the following technical scheme:

[0034] A preparation method of a hydrophobic protective glue, comprising the following steps:

[0035] The hydrophobic fumed silica is mixed and dispersed with part of the solvent oil to obtain a pre-dispersion system, the MQ resin, the composite silicone oil and the remaining solvent oil are mixed and dispersed to obtain a silicone oil system, and the pre-dispersion system is added to the silicone oil system and stirred, and then vacuum degassing is performed to obtain the hydrophobic protective glue.

[0036] In summary, the application has at least one of the following beneficial technical effects:

[0037] The MQ resin, the hydrophobic fumed silica, the composite silicone oil and the solvent oil are used as the protective glue base material, the MQ resin Si-O-Si inorganic skeleton has good heat resistance, the hydrophobic fumed silica is added as a filler, and the specific polyurethane modified silicone oil, the epoxy modified silicone oil and the MQ resin have a synergistic high temperature resistance effect;

[0038] The polyurethane modified silicone oil and the epoxy modified silicone oil are simultaneously added in the composite silicone oil, the controllable micro phase separation occurs in the curing process, the uniform and stable micro-nano rough structure is spontaneously formed on the surface of the adhesive layer, and the crosslinked network is formed, the compactness is improved, and the dispersion and anchoring of the MQ resin and the filler are further promoted, and the high temperature resistance and the hydrophobic property of the protective adhesive are greatly improved.

[0039] The polyurethane modified silicone oil takes the hydroxyl silicone oil as the key raw material, hinders the penetration of water molecules, reduces the molecular chain entanglement, reduces the internal stress, and reduces the occurrence of cracking phenomenon in high temperature conditions; the carboxyl of itaconic acid and the hydroxyl of dipentaerythritol are subjected to polycondensation reaction to obtain a macromolecular polycondensation compound grafted in the polyurethane modified silicone oil, and the crosslinking density can be significantly improved.

[0040] The amino silicone oil, 2,6-dichlorobenzonitrile, potassium carbonate, bisphenol A and epichlorohydrin are used to prepare the epoxy modified silicone oil, the molecular structure of which has an aryl ether bond, a cyano group and an epoxy group, and the high temperature resistance, water resistance and mechanical strength of the protective adhesive can be significantly improved; the rigid aromatic ring of the polyarylether nitrile is grafted in the high-branched segment of the polyurethane modified silicone oil, and the controllable and stable micro-nano rough structure is further promoted, and the high temperature resistance and the hydrophobic property of the system as a whole are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The 3D phase diagram of the protective adhesive of the formula of Example 3 is shown in the following table. DETAILED DESCRIPTION

[0042] The application will be further described in detail in combination with the following examples:

[0043] Raw material description: all the raw materials in the examples can be obtained by market purchase; wherein, the solvent oil is obtained by mixing n-heptane (CAS number: 142-82-5) and n-octane (CAS number: 111-65-9) in a mass ratio of 1:1, the hydrophobic fumed silica is DOWSIL R202, the amino silicone oil is Hubei Yaimaid Biological Medicine Co., Ltd. type 3533, the hydroxyl silicone oil is purchased from Shandong Gungong Chemical Co., Ltd. JN-204, 1000 viscosity; the MQ resin is purchased from Guangzhou Rongda Chemical Co., Ltd. B-1900; the ordinary epoxy resin is epoxy resin 6101. Example 1

[0044] Preparation of polyurethane modified silicone oil:

[0045] After 36.49 g of itaconic acid (CAS No.: 97-65-4) was mixed with 13.51 g of dipentaerythritol (CAS No.: 126-58-9), 250 ml of N-methylpyrrolidone (CAS No.: 872-50-4) was added, and the mixture was stirred at a speed of 1000 rpm under the protection of nitrogen at 100℃ for 60 min to obtain a pre-preparation, and then the temperature was increased to 130℃ and reacted for 8 h. After the mixture was cooled to 25℃, the product was added to xylene (CAS No.: 1330-20-7), and the mixture was centrifuged at a speed of 400 rpm for 5 min. The supernatant was removed, and the precipitated solid was separated and dried in an oven at 80℃ for 10 h to obtain a macromolecular polycondensation complex. 44.4 g of isophorone diisocyanate (CAS No.: 4098-71-9) was mixed with 44.4 g of dimethylformamide (CAS No.: 68-12-2) to obtain a mixed solution. 21 g of diethanolamine (CAS No.: 111-42-2) was mixed with 21 g of dimethylformamide to obtain a diethanolamine solution. The diethanolamine solution was added to the mixed solution under the condition of an ice water bath, and the mixture was reacted for 2 h, and then the temperature was increased to 70℃ and reacted for 120 min. Then, 10.0 g of hydroxyl silicone oil was added, and the mixture was stirred at the protection temperature for 2 h. Finally, the prepared macromolecular polycondensation complex was added, and the mass fraction of the macromolecular polycondensation complex was 9.5 wt%. The mixture was capped to obtain a polyurethane modified silicone oil.

[0046] Preparation of epoxy modified silicone oil:

[0047] Mix 2,6-dichlorobenzonitrile (CAS No: 1194-65-6), bisphenol A (CAS No: 80-05-7) and potassium carbonate in a molar ratio of 1:1:1, add N-methyl pyrrolidone and toluene as solvents, the mass ratio of raw materials and solvents is 1:10, stir at a speed of 500 rpm and dehydrate, after dehydration, remove excess water to obtain a mixture, heat the mixture to 200°C, stir for 80 min, obtain the reaction product, dilute with N-methyl pyrrolidone, then wash with hydrochloric acid solution and boiling water until neutral, after washing, add to anhydrous ethanol for reflux purification, and wash again with anhydrous ethanol, dry in an oven at 100°C for 24 h to obtain a polyarylether nitrile; mix 60 g of polyarylether nitrile with 30 mL of epichlorohydrin (CAS No: 106-89-8), add 2 g of sodium hydroxide solution, react at 70°C oil bath under nitrogen protection for 6 h, after reaction, cool to 25°C naturally, add 200 mL of acetone to absorb moisture, adjust the system to pH 7 with dilute hydrochloric acid, and remove the residual sodium hydroxide, wash with deionized water, then remove acetone and unreacted epichlorohydrin by rotary evaporation to obtain a modified epoxy resin; mix 5 g of amino silicone oil, 10 mL of dimethylformamide and the above modified epoxy resin, stir at a speed of 200 rpm at a water bath temperature of 60°C for 30 min, and remove excess dimethylformamide by rotary evaporation to obtain an epoxy-modified silicone oil.

[0048] Preparation of composite silicone oil:

[0049] Mix 53.33 g of epoxy-modified silicone oil with 26.67 g of polyurethane-modified silicone oil and stir at a speed of 200 rpm for 30 min to obtain a composite silicone oil.

[0050] Preparation of hydrophobic protective glue:

[0051] Mix the hydrophobic fumed silica with the solvent oil and disperse at a speed of 1500 rpm for 20 min to obtain a pre-dispersion system; mix the MQ resin, composite silicone oil and solvent oil, heat to 50°C, and stir at a speed of 800 rpm for 30 min to obtain a silicone oil system; add the pre-dispersion system to the silicone oil system, stir at a speed of 1000 rpm for 20 min, and then stir at a speed of 800 rpm for 15 min, and vacuum degassing to obtain the hydrophobic protective glue; wherein, according to mass percentage, the MQ resin is 9wt%, the hydrophobic fumed silica is 1wt%, the composite silicone oil is 1wt%, and the balance is solvent oil. Example 2

[0052] Preparation of polyurethane-modified silicone oil:

[0053] Mix 37.18 g of itaconic acid with 12.82 g of dipentaerythritol, add 250 ml of N-methyl pyrrolidone, and magnetically stir at a speed of 1000 rpm under the protection of nitrogen at 100℃ for 60 min to obtain a pre-preparation, then heat to 130℃ and react for 8 h, cool to 25℃, then add the product to xylene, centrifuge at a speed of 400 rpm for 5 min to remove the supernatant, separate the precipitated solid, and dry in an oven at 80℃ for 10 h to obtain a macromolecular polycondensation complex; mix 44.4 g of isophorone diisocyanate with 44.4 g of dimethylformamide to obtain a mixed solution, mix 21 g of diethanolamine with 21 g of dimethylformamide to obtain a diethanolamine solution, add the diethanolamine solution to the mixed solution under the condition of an ice water bath, react for 2 h, then heat to 70℃ and react for 120 min, then add 10.0 g of hydroxyl silicone oil, stir at the protection temperature for 2 h, and finally add the prepared macromolecular polycondensation complex, the mass fraction of the macromolecular polycondensation complex being 10.5 wt%, to carry out end capping to obtain a polyurethane modified silicone oil.

[0054] Preparation of epoxy modified silicone oil:

[0055] Mix 2,6-dichlorobenzonitrile, bisphenol A, and potassium carbonate in a molar ratio of 1:1:1, add N-methyl pyrrolidone and toluene as solvents, the mass ratio of raw materials and solvents being 1:10, heat to 140℃, stir at a speed of 500 rpm and dehydrate, remove excess water after dehydration to obtain a mixture, heat the mixture to 200℃, stir for 100 min to obtain a reaction product, dilute with N-methyl pyrrolidone, then wash with hydrochloric acid solution and boiling water until neutral, add to anhydrous ethanol after washing to reflux and purify, wash again with anhydrous ethanol, and dry in an oven at 100℃ for 24 h to obtain a polyarylether nitrile; mix 60 g of the polyarylether nitrile with 30 mL of epichlorohydrin, add 2 g of sodium hydroxide solution, react at 70℃ in an oil bath under the protection of nitrogen for 6 h, naturally cool to 25℃ after reaction, add 200 mL of acetone to absorb moisture, adjust the system to pH 7 with dilute hydrochloric acid, and remove residual sodium hydroxide, wash with deionized water, then remove acetone and unreacted epichlorohydrin by rotary evaporation to obtain a modified epoxy resin, mix 5 g of amino silicone oil, 10 mL of dimethylformamide, and the modified epoxy resin, stir at a speed of 200 rpm at a water bath temperature of 60℃ for 30 min, and remove excess dimethylformamide by rotary evaporation to obtain an epoxy modified silicone oil.

[0056] Preparation of composite silicone oil:

[0057] Mix 55 g of epoxy modified silicone oil with 25 g of polyurethane modified silicone oil, stir at a speed of 200 rpm for 30 min to obtain a composite silicone oil.

[0058] Preparation of hydrophobic protective glue:

[0059] The hydrophobic fumed silica was mixed and dispersed with solvent oil at a rotation speed of 1500 rpm for 20 min to obtain a pre-dispersion system; the MQ resin, composite silicone oil and solvent oil were mixed, heated to 50℃, and stirred at a rotation speed of 800 rpm for 30 min to obtain a silicone oil system; the pre-dispersion system was added to the silicone oil system and stirred at a rotation speed of 1000 rpm for 20 min and at a rotation speed of 800 rpm for 15 min, and then vacuum degassing was performed to obtain the hydrophobic protective glue; wherein, according to mass percentage, the MQ resin is 11wt%, the hydrophobic fumed silica is 1.5wt%, the composite silicone oil is 4wt%, and the balance is solvent oil. Example 3

[0060] Preparation of polyurethane modified silicone oil:

[0061] After mixing 36.84g of itaconic acid with 13.16g of dipentaerythritol, 250ml of N-methyl pyrrolidone was added, and magnetic stirring was performed at a rotation speed of 1000 rpm, and the pre-preparation was obtained by reacting at 100℃ under nitrogen protection for 60 min, and then the temperature was increased to 130℃ and reacted for 8h, and after cooling to 25℃, the product was added to xylene, centrifuged at a rotation speed of 400 rpm for 5 min, the supernatant was removed, and the precipitated solid was separated and dried in an oven at 80℃ for 10h to obtain a macromolecular condensation complex; 44.4g of isophorone diisocyanate was mixed with 44.4g of dimethylformamide to obtain a mixed liquid, 21g of diethanolamine was mixed with 21g of dimethylformamide to obtain a diethanolamine solution, and the diethanolamine solution was added to the mixed liquid under the condition of ice water bath, reacted for 2h, then the temperature was increased to 70℃, reacted for 120min, then 10.0g of hydroxyl silicone oil was added, and the temperature was stirred for 2h, finally the prepared macromolecular condensation complex was added, the mass percentage of the macromolecular condensation polymer was 10wt%, and the end capping was performed to obtain the polyurethane modified silicone oil.

[0062] Preparation of epoxy modified silicone oil:

[0063] Mix 2,6-dichlorobenzonitrile, bisphenol A and potassium carbonate in a proportion of 1:1:1 by mole, the mass ratio of raw materials and solvents is 1:10, add N-methyl pyrrolidone and toluene as solvents, stir at a speed of 500 rpm and dehydrate at a temperature of 140℃, after dehydration, remove excess water to obtain a mixture, heat the mixture to 200℃, stir for 90 min, obtain the reaction product, dilute with N-methyl pyrrolidone, then wash with hydrochloric acid solution and boiling water until neutral, after washing, add to anhydrous ethanol for reflux purification, and wash again with anhydrous ethanol, dry in an oven at 100℃ for 24 h, obtain polyarylether nitrile; mix 60 g of polyarylether nitrile with 30 mL of epichlorohydrin, add 2 g of sodium hydroxide solution, react at 70℃ oil bath under the condition of nitrogen protection for 6 h, after reaction, naturally cool to 25℃, add 200 mL of acetone to absorb moisture, adjust the system to pH 7 with dilute hydrochloric acid, and remove the residual sodium hydroxide, after washing with deionized water, remove acetone and unreacted epichlorohydrin by rotary evaporation, obtain modified epoxy resin, mix 5 g of amino silicone oil, 10 mL of dimethylformamide and the above modified epoxy resin, stir at a speed of 200 rpm at a water bath temperature of 60℃ for 30 min, remove excess dimethylformamide by rotary evaporation, obtain epoxy modified silicone oil.

[0064] Preparation of composite silicone oil:

[0065] Mix 54.19 g of epoxy modified silicone oil with 25.81 g of polyurethane modified silicone oil, stir at a speed of 200 rpm for 30 min, obtain composite silicone oil.

[0066] Preparation of hydrophobic protective glue:

[0067] Mix and disperse hydrophobic fumed silica with solvent oil at a speed of 1500 rpm for 20 min to obtain a pre-dispersion system; mix MQ resin, composite silicone oil and solvent oil, heat to 50℃, stir at a speed of 800 rpm for 30 min to obtain a silicone oil system, add the pre-dispersion system to the silicone oil system, stir at a speed of 1000 rpm for 20 min, then add small molecule silicone oil, stir at a speed of 800 rpm for 15 min, vacuum degassing to obtain hydrophobic protective glue; wherein, according to mass percentage, the mass percentage of MQ resin is 10 wt%, the mass percentage of hydrophobic fumed silica is 1.3 wt%, the mass percentage of composite silicone oil is 2 wt%, and the rest is solvent oil. Example 4

[0068] Example 4 is based on Example 3, in Example 4, when preparing polyurethane modified silicone oil, itaconic acid used is 34.37 g, dipentaerythritol is 15.63 g. Example 5

[0069] Example 5 is based on Example 3, and in Example 5, 38.64 g of itaconic acid and 13.51 g of dipentaerythritol are used in the preparation of the polyurethane-modified silicone oil. Example 6

[0070] Example 6 is based on Example 3, and in Example 6, the mass ratio of the macromolecular condensate is 8 wt% in the preparation of the polyurethane-modified silicone oil. Example 7

[0071] Example 7 is based on Example 3, and in Example 7, the mass ratio of the macromolecular condensate is 12 wt% in the preparation of the polyurethane-modified silicone oil. Example 8

[0072] Example 8 is based on Example 3, and in Example 8, the amount of the epoxy-modified silicone oil used is 50.37 g, and the amount of the polyurethane-modified silicone oil used is 29.63 g in the preparation of the composite silicone oil. Example 9

[0073] Example 9 is based on Example 3, and in Example 9, the amount of the epoxy-modified silicone oil used is 57.14 g, and the amount of the polyurethane-modified silicone oil used is 22.86 g in the preparation of the composite silicone oil. Example 10

[0074] Example 10 is based on Example 3, and in Example 10, the capped macromolecular condensate is replaced by di-n-butylamine in the preparation of the polyurethane-modified silicone oil. Example 11

[0075] Example 11 is based on Example 3, and in Example 11, the modified epoxy resin of the epoxy-modified silicone oil is replaced by a common epoxy resin in the preparation of the composite silicone oil.

[0076] Comparative Example 1

[0077] Comparative Example 1 is based on Example 3, and in Comparative Example 1, the composite silicone oil only includes the epoxy-modified silicone oil, i.e., the polyurethane-modified silicone oil is replaced by an equal amount of the epoxy-modified silicone oil.

[0078] Comparative Example 2

[0079] Comparative Example 2 is based on Example 3, and in Comparative Example 2, the composite silicone oil only includes the polyurethane-modified silicone oil, i.e., the epoxy-modified silicone oil is replaced by an equal amount of the polyurethane-modified silicone oil.

[0080] Performance Test

[0081] The samples of Examples 1-11 and Comparative Examples 1-2 were sampled and subjected to the following performance tests:

[0082] (1) Water resistance test

[0083] With GB / T 1733-1993 as the detection reference, the sample was coated on the surface of the tinplate with a thickness of 20 μm, and after the surface was dried for 30 min, it was dried at 50℃ for 1 h, and the water resistance of the sample was tested,

[0084] With GB / T 1037-2023 as the detection reference, the sample was uniformly coated on the glass substrate to form a film with a thickness of (200±10) μm, and was sealed in a moisture permeable cup (with anhydrous calcium chloride as a drying agent in the cup), and was placed in a constant temperature and humidity chamber at 38℃ and a relative humidity of 90%. Every 24 h, the weight was measured, and the water vapor transmission rate per unit area per 24 h was calculated by the mass change, and the test was continuously conducted for 5 days;

[0085] Each sample was tested 3 times, the average value was taken, and the test results were filled in Table 1.

[0086] (2) High temperature resistance test

[0087] Each sample was coated on the surface of the steel and cured at 180℃ for 2 h, and the glue layer was observed.

[0088] (3) Contact angle test

[0089] With GB / T 24368-2009 as the detection reference, the contact angle of the sample was tested by a static contact angle measuring instrument, and the test results were filled in Table 1.

[0090] Table 1 Performance test results of Examples 1-11 and Comparative Examples 1-2

[0091]

[0092] As can be seen from Table 1, the water resistance of Examples 1-3 is all above 520 h, and the water vapor transmission rate is all below 0.90 g / (m 2 ·24 h), which shows that the hydrophobic protective glue prepared in the application has good water resistance; Example 1-9 shows the stability of the glue layer at high temperature, which shows that the hydrophobic protective glue prepared in the application has good high temperature resistance, and the contact angle of Example 1-3 is all above 135°, which shows that the hydrophobic protective glue prepared in the application has good hydrophobicity. Figure 1 Further, it is further shown that the glue layer prepared in the application forms a micro-nano hydrophobic structure after curing.

[0093] The mass ratio between itaconic acid and dipentaerythritol in the preparation of polyurethane modified silicone oil in Example 4 and Example 5 is not within the range defined in the present application. When the amount of itaconic acid is too large, there are too many carboxyl groups in the system, which react with the hydroxyl groups of dipentaerythritol to form more linear structures, affecting the micro-nano structure, reducing the contact angle, and affecting the overall heat resistance of the system. If the amount of itaconic acid is too small, it may affect the bonding with epoxy resin and deteriorate the continuity of the micro-nano structure, thereby affecting the heat resistance and hydrophobicity.

[0094] The mass ratio of macromolecular condensate in the preparation of polyurethane modified silicone oil in Example 6 and Example 7 is not within the range defined in the present application. When the content of macromolecular condensate is too low, the crosslinking points with epoxy resin are reduced, the crosslinking density of polyurethane modified silicone oil is insufficient, the degree of microphase separation is weak, and the stable micro-nano structure is deteriorated. When the mass ratio of macromolecular condensate is too large, microgels or uneven local crosslinking are formed, the uniformity of the prepared hydrophobic protective glue is reduced, and the performance of the glue layer is deteriorated.

[0095] The mass ratio between epoxy modified silicone oil and polyurethane modified silicone in the preparation of composite silicone oil in Example 8 and Example 9 is not within the range defined in the present application. When the mass ratio of epoxy modified silicone oil is too low or too high, the crosslinking and the formation of stable micro-nano structure of the system are deteriorated, so the performance of Example 8 and Example 9 is reduced.

[0096] In Example 10, macromolecular condensate is replaced by di-n-butylamine in the preparation of polyurethane modified silicone oil, which reduces the activity and affects the compatibility with modified epoxy resin, deteriorating the formation of controllable micro-nano structure, thereby reducing the performance of the prepared hydrophobic protective glue.

[0097] In Example 11, the modified epoxy resin in the epoxy modified silicone oil is replaced by ordinary epoxy resin, which has no rigid heterocycle, and the thermal stability and rigidity are reduced. Moreover, it cannot cooperate with polyurethane modified silicone oil to construct stable micro-nano structure and crosslinking network, so the performance of Example 11 is reduced.

[0098] The composite silicone oil in Comparative Example 1 only includes epoxy modified silicone oil without adding polyurethane modified silicone oil, which cannot form micro-nano rough structure and deteriorate the crosslinking of the system, resulting in a significant decrease in hydrophobicity and high temperature resistance.

[0099] The composite silicone oil in Comparative Example 2 only includes polyurethane modified silicone oil. Single polyurethane modified silicone oil cannot form uniform micro-nano rough structure due to uncontrollable microphase separation, and has no epoxy-polyurethane interpenetrating network support, so the high temperature resistance is also reduced. Therefore, the performance of Comparative Example 1 is reduced.

[0100] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and the technical scope must be determined according to the scope of claims.

Claims

1. A hydrophobic protective adhesive, characterized in that: According to mass percentage, it includes the following components: The composition includes 5-20 wt% MQ resin, 0.5-5 wt% hydrophobic fumed silica, 1-4 wt% composite silicone oil, and the balance being solvent oil. The composite silicone oil includes epoxy-modified silicone oil and polyurethane-modified silicone oil. The hydrophobic protective adhesive forms a micro-nano rough structure after coating and curing. The preparation method of the polyurethane modified silicone oil includes: Itaconic acid and dipentaerythritol were mixed and reacted to obtain a macromolecular polycondensation complex; isophorone diisocyanate was reacted with diethanolamine to obtain a prepolymer; hydroxyl silicone oil was added to the prepolymer and reacted; finally, the macromolecular polycondensation complex was added and reacted to obtain polyurethane modified silicone oil. The mass ratio of itaconic acid to dipentaerythritol is (2.7-2.9):1; The added macromolecular polycondensation complex accounts for 9.5-10.5 wt% of the total amount of prepolymer and hydroxyl silicone oil. The preparation method of the epoxy-modified silicone oil includes: 2,6-Dichlorobenzonitrile and bisphenol A were reacted to obtain polyarylene ether nitrile; polyarylene ether nitrile was reacted with epichlorohydrin to obtain modified epoxy resin; amino silicone oil and modified epoxy resin were mixed and reacted to obtain epoxy modified silicone oil. The mass ratio of the epoxy-modified silicone oil to the polyurethane-modified silicone oil is 2-2.2:

1.

2. The hydrophobic protective adhesive according to claim 1, characterized in that: The mass ratio of the epoxy-modified silicone oil to the polyurethane-modified silicone oil is 2.1:

1.

3. The hydrophobic protective adhesive according to claim 1, characterized in that: The composite silicone oil is prepared by the following method: A composite silicone oil is obtained by uniformly mixing epoxy-modified silicone oil and polyurethane-modified silicone oil.

4. A method for preparing a hydrophobic protective adhesive according to any one of claims 1-3, characterized in that: Includes the following steps: Hydrophobic fumed silica was mixed and dispersed with a portion of solvent oil to obtain a pre-dispersed system. MQ resin, composite silicone oil, and the remaining solvent oil were mixed and dispersed to obtain a silicone oil system. The pre-dispersed system was added to the silicone oil system and stirred. After vacuum degassing, a hydrophobic protective adhesive was obtained.

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