Water-based resin, preparation method and application

Abstract

The invention provides water-based resin as well as a preparation method and application thereof. The water-based resin is prepared from the following components in parts by weight: 10 to 30 parts of silane A, and the silane A contains an epoxy group; 8 to 20 parts of silane B, wherein the silane B contains amino groups; 1 to 5 parts of silane C, wherein the silane C is POSS (Polyhedral Oligomeric Silsesquioxane) modified silane; 1 to 2 parts of PVA; 20 to 50 parts of silica sol and 80 to 150 parts of deionized water; a prepolymer aqueous solution is formed between silane to provide organic / inorganic dual crosslinking, a mixed solution provides a flexible chain segment and hydrophilic dispersibility, and silane C provides a nanoscale rigid core, and the three are combined to form a multistage composite network from molecular scale to nanoscale, so that flexibility and high strength are both considered; the insulating property, the high temperature resistance and the flame retardance of the resin material are obviously improved; and a water-soluble system is adopted, so that the coating is environment-friendly, solvent-free and suitable for the fields of electronic packaging, insulating coatings, high-temperature resistance, flame retardance and the like.

Description

Technical Field

[0001] This invention relates to the field of insulating coating technology, and in particular to an aqueous resin, its preparation method, and its application. Background Technology

[0002] With the rapid development of the electronics industry, devices are constantly evolving towards miniaturization, high performance, and high reliability, placing higher demands on electrical insulation materials. Ideal insulation materials not only need excellent electrical insulation properties but also should remain stable at high temperatures and possess flame-retardant characteristics to meet the requirements of complex service conditions. Traditional organic polymer resins, such as epoxy resins, phenolic resins, and polyester resins, are widely used in electronic packaging and insulation due to their mature processes and balanced performance. However, these materials often suffer from limited heat resistance, poor flammability, and limited application in aqueous systems.

[0003] To address these shortcomings, inorganic-organic hybrid materials have received widespread attention in recent years. Silane compounds possess a hydrolytic condensation structure, enabling them to form a three-dimensional cross-linked Si-O-Si network in aqueous conditions, thus endowing the materials with excellent thermal stability and flame retardant properties. In particular, organic functional silanes, such as γ-glycidoxypropylsilane, aminosilane, and allylsilane, can chemically bond with organic resins and also undergo sol-gel reactions in aqueous phases, giving them a natural advantage in the preparation of waterborne high-temperature resistant resins. However, currently common water-soluble silane resins still have some problems: firstly, the system has poor stability and is prone to gelation or phase separation during storage or film formation; secondly, despite the introduction of the Si-O-Si network, the overall heat resistance is still insufficient to meet the requirements of long-term operation of high-temperature electronic components; and thirdly, there is often a trade-off between insulation and flame retardancy, and achieving both remains a challenge.

[0004] Against this backdrop, researchers have attempted to improve the overall performance of water-soluble silane resins by introducing various modification strategies. For example, some reports suggest improving dispersibility and film-forming properties through blending or reaction with water-soluble polymers such as polyvinyl alcohol and polyacrylic acid; others utilize nano-organic-inorganic hybrid units such as cage-like silsesquioxanes (POSS) to enhance the thermal stability and rigid framework structure of materials, thereby improving their high-temperature resistance and insulation properties. While these advances have promoted the development of waterborne silane resins to some extent, existing solutions generally suffer from complex processes, high material costs, or failure to simultaneously achieve ideal levels in electrical insulation, heat resistance, and flame retardancy.

[0005] Therefore, how to further improve the thermal stability, flame retardancy, and electrical insulation of silane resins while maintaining the advantages of water-based processing has become a pressing problem in the current technological field. This is also a key area of ​​ongoing research and industrial application exploration. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide an aqueous resin, its preparation method, and its application, in order to overcome the problem that the existing resin compositions fail to simultaneously achieve ideal levels in terms of electrical insulation, heat resistance, and flame retardancy.

[0007] The technical solution of the present invention: In a first aspect, the present invention provides an aqueous resin, wherein the aqueous resin comprises, by weight, the following components: 10-30 parts of silane A, wherein silane A contains epoxy groups; 8-20 parts of silane B, wherein silane B contains an amino group; 1-5 parts of silane C, wherein the silane C is a POSS-modified silane; 1-2 PVA sheets; 20-50 parts silica sol; And 80-150 parts of deionized water.

[0008] In some embodiments, the silane A is selected from one or more combinations of γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane.

[0009] In some embodiments, the silane B is selected from one or more combinations of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, n-butylaminopropyltrimethoxysilane, n-butylaminopropyltriethoxysilane, bis(trimethoxysilylpropyl)ethylenediamine, and bis(triethoxysilylpropyl)ethylenediamine.

[0010] In some embodiments, the method for preparing the silane C includes the following steps: Step 1: Add solvent and POSS material to the reactor and stir until homogeneous; Step 2: Slowly add H2N-PEG-OH, gently heat and stir to carry out the reaction. After the reaction is completed, cool and remove the solvent by vacuum distillation to obtain PEG-grafted POSS material; Step 3: Take the PEG-grafted POSS material prepared in Step 2, dissolve it in an anhydrous solvent, stir under a nitrogen atmosphere, add 3-isocyanate propyltriethoxysilane, heat and stir to carry out the reaction, after the reaction is completed, evaporate the solvent, wash to remove free small molecules, and obtain silane C.

[0011] In some embodiments, the POSS material is Glycidyl-POSS (CAS#68611-45-0).

[0012] In some embodiments, the molar ratio of the POSS material to H2N-PEG-OH is 1:4-5.

[0013] In some embodiments, the reaction temperature in step 2 is 40-60°C and the reaction time is 8-16 hours.

[0014] In some embodiments, the mass ratio of the PEG-grafted POSS material in step 3 to 3-isocyanate propyltriethoxysilane is 6:0.5-1.5.

[0015] In some embodiments, the reaction temperature in step 3 is 50-70°C, and the reaction time is 6-12 hours.

[0016] In some embodiments, the molecular weight of the PVA is 30,000 to 50,000, which ensures both good resin dispersion compatibility and a certain degree of molecular chain flexibility, enabling it to synergistically stabilize the distribution of components in the resin system.

[0017] In some embodiments, the silica sol is an alkaline silica sol, and the particle size of the nano-silica in the silica sol is 10nm-100nm; further, the particle size of the nano-silica is 20nm-30nm.

[0018] In a second aspect, the present invention provides a method for preparing the aqueous resin, specifically comprising the following steps: Step 1: Add some silane A and silane B to the reactor, stir and heat to react, then cool down, add acid and deionized water, and continue to heat to react to prepare a prepolymer aqueous solution; Step 2: Add deionized water and PVA to the reactor, heat and stir until homogeneous, cool down and add silane A dropwise, add ammonia to adjust the pH, continue heating and reacting to prepare a modified PVA aqueous solution; Step 3: Add deionized water to the modified PVA aqueous solution, adjust the pH with acid, then add silica sol and silane C, heat and stir to react, then add the prepolymer aqueous solution, continue the reaction, then distill to remove byproducts, adjust the pH to 3.5-5, and prepare the waterborne resin.

[0019] In some embodiments, the ratio of silane A to silane B added in step 1 is 1-2:1; the reaction temperature of the stirring and heating reaction is 60-80℃, the stirring speed is 200-400rpm, and the reaction time is 12-14h.

[0020] In some embodiments, step 1 involves adding acid to adjust the pH to 3-6; further, acid is added to adjust the pH to 3.5-4.5.

[0021] In some embodiments, the ratio of PVA to silane A added in step 2 is 1:1; the ratio of PVA to deionized water added is 1:10.

[0022] In some embodiments, the reaction temperature for heating and stirring in step 2 is 80-100°C, the reaction time is 2-4 hours, and the stirring rate is 800-1000 rpm.

[0023] In some embodiments, the ratio of the mixed solution to deionized water added in step 3 is 1:4-8; the pH adjustment with acid is to adjust the pH to 2-3.

[0024] In some embodiments, the reaction temperature of the heating and stirring reaction in step 3 is 40-60°C, the reaction time is 1-2 hours, and the stirring rate is 200-40 rpm.

[0025] In some embodiments, the acid is one or more combinations of formic acid and acetic acid.

[0026] In a third aspect, the present invention provides the application of the waterborne resin in insulating, flame-retardant, and high-temperature resistant products in the electronic field.

[0027] Beneficial effects: 1. The prepolymer aqueous solution is the reaction product of silane A and silane B. The reaction of epoxy and amino groups forms strong covalent bonds, avoiding the instability caused by weak hydrogen bonds or physical crosslinking in a single sol system; thus improving thermal stability and flame retardancy. 2. The mixed solution is the reaction product of silane A and PVA. The epoxy group of silane A undergoes a ring-opening reaction with the hydroxyl group of PVA. At the same time, the alkoxy group of silane A undergoes hydrolysis and condensation in water, which can stabilize the aqueous solution system and give the resin good dispersibility and workability. The flexible segments of PVA are combined with the Si-O-Si inorganic skeleton to avoid the material being too brittle, improve the impact strength, and improve the insulation effect. 3. In silane C, POSS acts as a rigid cage-like Si-O-Si core, which undergoes an addition reaction with the –NCO group of isocyanate propylsilane, introducing a hydrolyzable and condensable –Si(OEt)3 group to form an organic-inorganic integrated hybrid nanounit. This significantly improves the thermal and dimensional stability of the material, helps reduce the dielectric loss of the material, and enhances the flame retardant effect.

[0028] 4. The prepolymer aqueous solution provides organic / inorganic dual crosslinking, the mixed solution provides flexible segments and hydrophilic dispersibility, and silane C provides a nanoscale rigid core. The combination of the three forms a multi-level composite network from the molecular scale to the nanoscale, which takes into account both flexibility and high strength, and significantly improves the insulation performance, high temperature resistance and flame retardancy of the resin material. Moreover, it adopts a water-soluble system, which is environmentally friendly and solvent-free, and is suitable for electronic packaging, insulating coating, high temperature resistance and flame retardancy and other fields. Detailed Implementation

[0029] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0030] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade. The H2N-PEG-OH used in the examples and comparative examples was purchased from Hunan Huateng Pharmaceutical Co., Ltd., CAS: 32130-27-1, No.: 10081; the Glycidyl-POSS material used in the examples and comparative examples has the CAS number: 68611-45-0.

[0031] Example 1 Step 1: By weight, under nitrogen protection, add 15 parts of silane A and 15 parts of silane B to a three-necked flask equipped with an electric stirrer and a reflux condenser. Heat to 70°C and react at 400 rpm for 12 hours. Then cool to 50°C, add 3 parts of formic acid and 40 parts of deionized water and stir until homogeneous. Adjust the pH to 4 with formic acid, heat to 60°C and continue the reaction for 2 hours to prepare a prepolymer aqueous solution. Step 2: Add 20 parts deionized water and 2 parts PVA to the reactor, heat to 90℃ and stir at 1000rpm for 2 hours until the mixture is homogeneous. After cooling to 45℃, add 2 parts silane A dropwise and add 10% ammonia to adjust the pH to 10. Heat to 60℃ and react for 2 hours. Then adjust the pH to 4 with formic acid to obtain a modified PVA aqueous solution. Step 3: Add 20 parts of deionized water to the modified PVA aqueous solution, adjust the pH to 3 with formic acid, then add 20 parts of silica sol and 5 parts of the silane C prepared above, heat to 60℃ and stir at 400rpm for 2h to react, then add the prepolymer aqueous solution prepared in step 1, continue to react for 2h, then distill at 70℃ for 2h to remove byproducts, adjust the pH to 4 with formic acid to obtain the aqueous resin.

[0032] In the above steps, silane A is γ-glycidoxypropyltrimethoxysilane, silane B is γ-aminopropyltrimethoxysilane, and the preparation method of silane C is as follows; the PVA is model 2699, and the silica sol is Nissan Chemical's ST-O-40.

[0033] The preparation steps of silane C are as follows: Step 1: Add 50 mL of DMF solvent and 10 mmol of Glycidyl-POSS material to the reactor and stir until homogeneous; Step 2: Slowly add 45 mmol H2N-PEG-OH at room temperature, heat to 50℃ and stir for 10 h. After the reaction is completed, cool and remove the solvent by vacuum distillation to obtain PEG-grafted POSS material. Step 3: Take 6g of the PEG-grafted POSS material prepared in Step 2, dissolve it in 20mL of anhydrous DMF, stir it evenly under a nitrogen atmosphere, add 1g of 3-isocyanate propyltriethoxysilane, heat and stir at 50℃ for 12h, after the reaction is completed, evaporate the solvent, wash to remove free small molecules, and obtain silane C.

[0034] Example 2 The preparation steps are basically the same as in Example 1, except that silane A is γ-glycidoxypropyltriethoxysilane, silane B is n-butylaminopropyltrimethoxysilane, and acetic acid is used instead of formic acid.

[0035] Example 3 The preparation steps are basically the same as in Example 1, except that silane A is γ-glycidoxypropyltriethoxysilane and silane B is bis(triethoxysilylpropyl)ethylenediamine.

[0036] Comparative Example 1 The preparation steps are basically the same as in Example 1, except that silane A is γ-glycidoxypropyltriethoxysilane and silane B is 3-(phenylamino)propyltrimethoxysilane.

[0037] Comparative Example 2 The preparation steps are basically the same as in Example 1, except that the preparation steps for silane C are as follows: Step 1: Add 50 mL of DMF solvent and 10 mmol of Glycidyl-POSS material to the reactor and stir until homogeneous; Step 2: Add 1g of 4-trimethoxysilylbutanol, heat and stir at 50℃ for 12h. After the reaction is complete, evaporate the solvent and wash to remove free small molecules to obtain silane C.

[0038] Comparative Example 3 The preparation steps are as follows: Step 1: Add 17 parts of silane A, 15 parts of silane B, 5 parts of silane C, 2 parts of PVA and 20 parts of silica sol to 80 parts of deionized water, heat to 60℃ and stir at 400rpm for 2 hours to react, then distill at 70℃ for 2 hours to remove byproducts, adjust the pH to 4 with formic acid to obtain waterborne resin.

[0039] In the above steps, silane A is γ-glycidoxypropyltrimethoxysilane, silane B is γ-aminopropyltrimethoxysilane, and the preparation method of silane C is the same as in Example 1; the PVA is model 2699, and the silica sol is model ST-O-40 from Nissan Chemical.

[0040] Comparative Example 4 The preparation steps are basically the same as in Example 1, except that the amount of silane B added in step 1 is 0.

[0041] Comparative Example 5 The preparation steps are basically the same as in Example 1, except that the amount of PVA added in step 2 is 0.

[0042] Comparative Example 6 The preparation steps are basically the same as in Example 1, except that silane C in step 3 is replaced with an equal amount of silane A.

[0043] Performance testing The aqueous resin materials prepared in the examples and comparative examples were uniformly coated onto the surface of the substrate, dried and cured in an oven at 120°C to form a coating film, and then experimental samples conforming to the test specifications were made for the following performance tests: 1. Conductivity test: Volume resistivity was determined according to GB / T 31838.2-2019, and a copper sheet was selected as the test sample; 2. Adhesion test: Adhesion test shall be conducted in accordance with the provisions of GB / T1720-1988; 3. Heat resistance test: Cut the test strip into small squares of 2cm*2cm, with three samples per group. Place them in a molten solder furnace at over 288℃ for 10 seconds and observe the highest temperature at which the resin material does not crack or pulverize. 4. Impact resistance: The impact resistance of water-based resins is tested according to GB / T1732-1993.

[0044] The data results are shown in Table 1.

[0045] Table 1 Test Data

[0046] As can be seen from the above examples and comparative examples, the reactive prepolymers formed by silane A and silane B form effective covalent bonds, avoiding the instability caused by weak hydrogen bonds or physical crosslinking in a single sol system, and improving thermal stability and flame retardancy. Therefore, based on the data, the adhesion, heat resistance and impact strength of the examples are improved compared with Comparative Example 3.

[0047] The flexible segments of PVA are combined with the Si-O-Si inorganic framework to avoid the material being too brittle, improve the impact strength, and improve the insulation effect. Therefore, the impact strength of the embodiment is better than that of Comparative Example 5.

[0048] POSS, as a rigid cage-like Si-O-Si core, forms an organic-inorganic integrated hybrid nanounit with silane, which can significantly improve the thermal stability and dimensional stability of the material and enhance the flame retardant effect. Therefore, the heat resistance of the embodiment is significantly better than that of Comparative Example 6.

[0049] The adhesion and impact strength of Comparative Example 1 decreased slightly, while the heat resistance increased slightly. This may be because when 3-(phenylamino)propyltrimethoxysilane was selected as silane B, the steric hindrance of the benzene ring in the prepolymer had a greater impact, which increased the instability in the sol system, reduced the dispersibility and workability of the resin components, and thus affected the overall performance.

[0050] This invention can also be implemented in various other ways. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A water-based resin, characterized in that, The aqueous resin comprises the following components in parts by weight: 10-30 parts of silane A, wherein silane A contains epoxy groups; 8-20 parts of silane B, wherein silane B contains an amino group; 1-5 parts of silane C, wherein the silane C is a POSS-modified silane; 1-2 PVA sheets; 20-50 parts silica sol; And 80-150 parts of deionized water.

2. The waterborne resin according to claim 1, characterized in that, The silane A is selected from one or more combinations of γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane.

3. The aqueous resin according to claim 1, characterized in that, The silane B is selected from one or more combinations of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, n-butylaminopropyltrimethoxysilane, n-butylaminopropyltriethoxysilane, bis(trimethoxysilylpropyl)ethylenediamine, and bis(triethoxysilylpropyl)ethylenediamine.

4. The waterborne resin according to claim 1, characterized in that, The method for preparing the silane C includes the following steps: Step 1: Add solvent and POSS material to the reactor and stir until homogeneous; Step 2: Slowly add H2N-PEG-OH, gently heat and stir to carry out the reaction. After the reaction is completed, cool and remove the solvent by vacuum distillation to obtain PEG-grafted POSS material; Step 3: Take the PEG-grafted POSS material prepared in Step 2, dissolve it in an anhydrous solvent, stir under a nitrogen atmosphere, add 3-isocyanate propyltriethoxysilane, heat and stir to carry out the reaction, after the reaction is completed, evaporate the solvent, wash to remove free small molecules, and obtain silane C.

5. The aqueous resin according to claim 4, characterized in that, The molar ratio of the added POSS material to H2N-PEG-OH is 1:4-5.

6. The aqueous resin according to claim 4, characterized in that, The mass ratio of the PEG-grafted POSS material to 3-isocyanate propyltriethoxysilane in step 3 is 6:0.5-1.

5.

7. The aqueous resin according to claim 4, characterized in that, The reaction temperature in step 2 is 40-60℃ and the reaction time is 8-16h; the reaction temperature in step 3 is 50-70℃ and the reaction time is 6-12h.

8. The method for preparing the aqueous resin according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Add some silane A and silane B to the reactor, stir and heat to react, then cool down, add acid and deionized water, and continue to heat to react to prepare a prepolymer aqueous solution; Step 2: Add deionized water and PVA to the reactor, heat and stir until homogeneous, cool down and add silane A dropwise, add ammonia to adjust the pH, continue heating and reacting to prepare a modified PVA aqueous solution; Step 3: Add deionized water to the modified PVA aqueous solution, adjust the pH with acid, then add silica sol and silane C, heat and stir to react, then add the prepolymer aqueous solution, continue the reaction, then distill to remove byproducts, adjust the pH to 3.5-5, and prepare the waterborne resin.

9. The method for preparing the aqueous resin according to claim 8, characterized in that, The ratio of silane A to silane B added in step 1 is 1-2:1; the ratio of PVA to silane A added in step 2 is 1:

1.

10. The application of the waterborne resin according to claims 1-7 in insulating, flame-retardant, and high-temperature resistant products in the electronic field.

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