A silicone-modified amine epoxy curing agent and a preparation method thereof

Abstract

The application discloses a kind of organic silicon modified amine epoxy curing agent and preparation method thereof, the curing agent structure is composed of organic silicon, phenol, amine structure, preparation method includes the following steps: (1) the phenolic compound of double bond substituent group, catalyst and hydrogen-containing silicone oil are stirred and mixed uniformly under 50~75 ℃ nitrogen atmosphere, then heated to 65~90 ℃ and react for 4~6h, then solvent is removed by evaporation to obtain organic silicon modified phenol;(2) polyamine, organic silicon modified phenol, aldehyde compound and solvent are mixed uniformly, stirred uniformly under 50~75 ℃ nitrogen atmosphere, then refluxed and react for 2~4h, after solvent is removed by evaporation to obtain organic silicon modified amine epoxy curing agent.The application solves the problem that the bonding performance of epoxy adhesive is poor in humid or underwater environment, effectively improves the bonding performance of epoxy adhesive in seawater, freshwater and other underwater environment, and provides technical support for the bonding and sealing of moisture-resistant and heat-resistant electronic packaging, deep-sea underwater marine equipment and facilities.

Description

An organosilicon-modified amine epoxy curing agent and its preparation method Technical Field

[0001] This invention relates to an epoxy adhesive, specifically to an organosilicon-modified amine epoxy curing agent and its preparation method. Background Technology

[0002] Epoxy resin has advantages such as high bonding strength, good thermal stability, high mechanical strength, and excellent electrical properties. Adhesives synthesized from epoxy resin are widely used in shipbuilding, construction, aerospace, electronic packaging and other fields.

[0003] However, epoxy resin itself is brittle and hygroscopic. When epoxy resin absorbs water, it will crack due to the vaporization and expansion of the water, resulting in insufficient underwater curing ability and deterioration of performance. This limits its application range and makes it unable to meet the requirements of fields such as electronic packaging and deep-sea exploration.

[0004] Epoxy curing agents are a key factor affecting the bonding performance of epoxy adhesives. Currently, the epoxy adhesive curing agents used in the market are mainly amine-based. In humid or underwater environments, the strong affinity of polar groups such as amines for water results in poor interaction between the polar groups at the adhesive-substrate interface, leading to poor bonding performance and failure to achieve ideal bonding results in humid or underwater environments. Therefore, modification of epoxy adhesive curing agents to meet the requirements of moisture- and heat-resistant electronic packaging and underwater curing is particularly urgent. Summary of the Invention

[0005] This invention provides an organosilicon-modified amine epoxy curing agent and its preparation method, which solves the problem of poor adhesion performance of epoxy adhesives in humid or underwater environments, and effectively improves the adhesion performance of epoxy adhesives in underwater environments such as seawater and freshwater. It can provide technical support for the bonding and sealing of moisture- and heat-resistant electronic packaging, deep-sea underwater marine equipment and facilities.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An organosilicon-modified amine epoxy curing agent, the structure of which is composed of organosilicon, phenol, and amine, has the following chemical structural formula:

[0008]

[0009] In the formula, R1 is a C2~C8 aliphatic chain alkyl or alicyclic alkyl, R2 is CH3-, C2H5- or Ph-, and R3 is a meta- or para-substituted C3~C 15 Aliphatic alkyl chain.

[0010] A method for preparing the above-mentioned organosilicon-modified amine epoxy curing agent includes the following steps:

[0011] Step (1) Phenolic compounds containing double bond substituents, catalysts and hydrogen-containing silicone oil are stirred and mixed evenly under a nitrogen atmosphere at 50~75℃, and then heated to 65~90℃ for 4~6h. The solvent is then evaporated to obtain organosilicon-modified phenol.

[0012] Step (2) Mix the polyamine, organosilicon-modified phenol, aldehyde compound, and solvent. Stir the mixture thoroughly at 50-75°C under a nitrogen atmosphere. Then reflux for 2-4 hours. After evaporating to remove the solvent, obtain the organosilicon-modified amine epoxy curing agent, wherein:

[0013] The mass ratio of the aldehyde compound, polyamine, hydrogen-containing silicone oil, and phenolic compound containing double bond substituents is 9~15:30~85:28~52:26~61;

[0014] The catalyst is at least one of platinum-based catalyst, rhodium-based catalyst, and ruthenium-based catalyst, and is used in an amount of 5-10 ppm of the reaction system;

[0015] The aldehyde compound is at least one of the following: a 37% (w / w) aqueous solution of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, benzaldehyde, and furfural.

[0016] The polyamine is at least one selected from polyetheramine EDR-148, diethylenetriamine, ethylenediamine, propylenediamine, pentanediamine, 2-methylpentanediamine, hexanediamine, triethylenetetramine, tetraethylenepentamine, isophorone diamine, and cyclohexanediamine.

[0017] The hydrogen-containing silicone oil is at least one of methyl hydrogen-containing silicone oil, ethyl hydrogen-containing silicone oil, phenyl hydrogen-containing silicone oil, and methyl ethyl hydrogen-containing silicone oil.

[0018] The phenolic compound containing a double bond substituent is at least one of 3-allylphenol, 4-allylphenol, 4-(2-methyl-2-allyl)phenol, and cashew phenol.

[0019] The solvent is at least one selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-hexane, cyclohexane, petroleum ether, tetrahydrofuran, ethyl acetate, acetone, benzene, toluene, dichloromethane, chloroform, and dichloroethane.

[0020] The above-mentioned organosilicon-modified amine epoxy curing agent can be applied to the field of bonding and sealing of equipment and facilities in moisture- and heat-resistant electronic packaging, marine and freshwater environments. When applying, the ratio of epoxy resin to curing agent by weight is 100:18~40.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention introduces an organosilicon-modified phenolic structure into a polyamine via the Mannich reaction, preparing an organosilicon-modified amine epoxy curing agent. Compared to traditional epoxy curing agents, this curing agent offers the following advantages: the contained organosilicon segments significantly enhance the toughness of the cured product, improve stress dispersion, and simultaneously improve its resistance to damp heat; this curing agent can not only cure epoxy resins at room temperature but also achieve underwater curing and bonding. Its phenolic structure enhances interfacial bonding, improving underwater adhesion performance. This curing agent can be used not only for damp heat-resistant electronic packaging but also for bonding and sealing in marine and freshwater environments, solving the technical challenge of poor underwater adhesion performance of epoxy adhesives and possessing broad application prospects. Attached Figure Description

[0023] Figure 1 shows the infrared spectrum of the organosilicon-modified amine epoxy curing agent prepared in Example 1;

[0024] Figure 2 is a scanning electron microscope image of the cured product of the organosilicon-modified amine epoxy curing agent prepared in Example 1. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0026] Example 1

[0027] Step 1) Mix 61 parts cashew phenol, 0.03 parts platinum catalyst and 52 parts phenyl hydrogen silicone oil evenly under a nitrogen atmosphere at 60°C, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon modified phenol CAD.

[0028] Step 2) Mix 74 parts of polyetheramine EDR-148, 100 parts of organosilicon-modified phenol CAD, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, organosilicon-modified amine epoxy curing agent S-148 is obtained, and its structural diagram is shown below:

[0029] .

[0030] Example 2

[0031] Step 1) Mix 61 parts cashew phenol, 0.03 parts platinum catalyst and 52 parts phenyl hydrogen silicone oil evenly under a nitrogen atmosphere at 60°C, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon modified phenol CAD.

[0032] Step 2) Mix 51 parts of diethylenetriamine (DETA), 100 parts of organosilicon-modified phenolic CAD, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, the organosilicon-modified amine epoxy curing agent S-DETA is obtained, and its structural diagram is shown below:

[0033] .

[0034] Example 3

[0035] Step 1) Mix 61 parts cashew phenol, 0.03 parts platinum catalyst and 52 parts phenyl hydrogen silicone oil evenly under a nitrogen atmosphere at 60°C, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon modified phenol CAD.

[0036] Step 2) Mix 37 parts of 1,3-propanediamine (PDA), 100 parts of organosilicon-modified phenolic CAD, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, the organosilicon-modified amine epoxy curing agent S-PDA is obtained, and its structural diagram is shown below:

[0037] .

[0038] Example 4

[0039] Step 1) Mix 27 parts of 3-allylphenol, 0.01 parts of platinum catalyst and 52 parts of phenyl hydrogen-containing silicone oil evenly under a nitrogen atmosphere at 60°C, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon-modified phenol AMC.

[0040] Step 2) Mix 74 parts of polyetheramine EDR-148, 67 parts of organosilicon-modified phenol AMC, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, organosilicon-modified amine epoxy curing agent S-148-2 is obtained, and its structural diagram is shown below:

[0041] .

[0042] Example 5

[0043] Step 1) Mix 41 parts of 3-allylphenol, 0.02 parts of platinum catalyst and 42 parts of methyl hydrogen silicone oil at 60°C under a nitrogen atmosphere, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon-modified phenol MMC.

[0044] Step 2) Mix 63 parts of diethylenetriamine (DETA), 82 parts of organosilicon-modified phenolic MMC, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, organosilicon-modified amine epoxy curing agent S-DETA-2 is obtained, and its structural diagram is shown below:

[0045] .

[0046] Example 6

[0047] Step 1) Mix 27 parts of 4-allylphenol, 0.01 parts of platinum catalyst and 52 parts of methyl hydrogen silicone oil at 60°C under a nitrogen atmosphere, then heat to 80°C and react for 5 hours. Then evaporate to remove the solvent to obtain organosilicon-modified phenol PMMC.

[0048] Step 2) Mix 37 parts of 1,3-propanediamine (PDA), 67 parts of organosilicon-modified phenol PMMC, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol until homogeneous. Stir at 60°C under a nitrogen atmosphere until homogeneous, then reflux for 3 hours. After evaporating to remove the solvent, organosilicon-modified amine epoxy curing agent S-PDA-2 is obtained, and its structural diagram is shown below:

[0049] .

[0050] Application Example 1

[0051] Step 1) The organosilicon-modified amine epoxy curing agents S-148, S-DETA, and S-PDA prepared in the examples were mixed with E-51 bisphenol A type epoxy resin in proportions of 40:100, 18:100, and 19:100, respectively, and cured at 25°C for 7 days to obtain the corresponding epoxy resin cured products S-148 / E51, S-DETA / E51, and S-PDA / E51.

[0052] Step 2) According to GB / T 1040.2-2022 standard, a rectangular low-carbon steel Q235 sheet with a sample size of 100mm × 25mm × 2mm is selected. Two copper wires with a diameter of 0.2mm are arranged in parallel as spacers to precisely control the thickness of the epoxy resin cured adhesive layer in the overlapping area of ​​the sample to 0.2mm, and a single-overlap sample is prepared. According to GB / T 1040.2-2022 standard, a dumbbell-shaped epoxy resin cured sample is prepared using a standard mold. According to GB / T 1843-2008 standard, an epoxy resin cured sample with a sample size of 80mm × 10mm × 4mm without notches is prepared.

[0053] Step 3) Perform tensile property tests on dumbbell-shaped specimens according to GB / T 1040.2-2022 standard; perform single-lap tensile shear strength tests on single-lap specimens according to GB / T 1040.2-2022 standard; and determine the impact resistance of unnotched epoxy resin cured specimens according to GB / T 1843-2008 standard. Five parallel samples were prepared for each group of experiments. After five consecutive valid tests, the arithmetic mean of the measured strength values ​​was taken as the final result. Specific performance details are shown in Table 1.

[0054] Table 1 Mechanical properties of epoxy resin cured products

[0055]

[0056] Application Example 2

[0057] Step 1) Mix the organosilicon-modified amine epoxy curing agent S-148 prepared in the example with E-51 bisphenol A type epoxy resin at a ratio of 40:100, and cure at 90°C for 2 hours to obtain epoxy resin cured product S-148 / E51.

[0058] Step 2) According to GB / T 1040.2-2022 standard, a rectangular low-carbon steel Q235 steel sheet with a sample size of 100mm×25mm×2mm is selected. Two copper wires with a diameter of 0.2mm are arranged in parallel as spacers. The thickness of the epoxy resin cured adhesive layer in the overlapping area of ​​the sample is precisely controlled to be 0.2mm to prepare a single overlapping sample.

[0059] Step 3) Using a temperature and humidity environmental test chamber, a constant environment of (85±2)℃ and (85±5)%RH was maintained inside the chamber to conduct a continuous 42-day accelerated damp heat aging test on the Q235 low carbon steel single lap joint specimen. The tensile shear strength was measured at four time points (0d, 14d, 28d, and 42d), and the specific properties are shown in Table 2.

[0060] Table 2. Resistance to damp heat aging of epoxy resin cured products

[0061]

[0062] Application Example 3

[0063] Step 1) Immerse rectangular low-carbon steel Q235 sheets (100mm × 25mm × 2mm) in deionized water or seawater at 25℃. While in the water, evenly apply adhesive systems S-148 / E51, S-DETA / E51, and S-PDA / E51 (composed of epoxy curing agent with 20wt% calcium oxide filler and epoxy resin) onto the Q235 steel sheets. Then, butt-bond two steel sheets underwater, fix them with clamps under pressure, and then cure them underwater at 25℃ for 7 days.

[0064] Step 2) Remove the bonded steel sheet that has been cured underwater for 7 days from the water and clean it. According to GB / T 1040.2-2022 standard, conduct a tensile shear test within 2 hours to test its tensile shear strength. The specific properties are shown in Table 3.

[0065] Table 3. Underwater bonding performance of epoxy adhesive systems

[0066]

[0067] This invention introduces an organosilicon-modified phenolic structure into a polyamine via the Mannich reaction, preparing an organosilicon-modified amine epoxy curing agent. Epoxy adhesives cured using this invention exhibit excellent mechanical properties, with high tensile shear strength retention under humid and hot conditions. The maximum tensile shear strength reaches 16.8 MPa in deionized water and 15.6 MPa in seawater. This indicates that the epoxy adhesive prepared from this curing agent can be applied to humid and hot electronic packaging, and to the bonding and sealing of equipment and facilities in marine and freshwater environments, demonstrating broad application prospects.

Claims

1. An organosilicon-modified amine epoxy curing agent, characterized in that... The chemical structural formula of the curing agent is as follows: In the formula, R1 is a C2~C8 aliphatic alkyl chain, alicyclic alkyl chain, -CH2CH2-O-CH2CH2-O-CH2CH2- or -CH2-CH2-NH-CH2-CH2-, R2 is CH3-, C2H5- or Ph-, and R3 is a meta- or para-substituted C3~C 15 Aliphatic alkyl chain.

2. A method for preparing the organosilicon-modified amine epoxy curing agent according to claim 1, characterized in that... The method includes the following steps: Step (1) A phenolic compound containing a double bond substituent, a catalyst, and a hydrogen-containing silicone oil are stirred and mixed evenly under a nitrogen atmosphere at 50-75°C, and then heated to 65-90°C for 4-6 hours. The solvent is then evaporated to obtain an organosilicon-modified phenol. The phenolic compound containing a double bond substituent is at least one of 3-allylphenol, 4-allylphenol, 4-(2-methyl-2-allyl)phenol, and cashew phenol. The hydrogen-containing silicone oil is at least one of methyl hydrogen-containing silicone oil, ethyl hydrogen-containing silicone oil, phenyl hydrogen-containing silicone oil, and methyl ethyl hydrogen-containing silicone oil. Step (2) Polyamine, organosilicon-modified phenol, and aldehyde compound are mixed. The material and solvent are mixed evenly and stirred at 50-75°C under a nitrogen atmosphere. The mixture is then refluxed for 2-4 hours. After evaporation to remove the solvent, an organosilicon-modified amine epoxy curing agent is obtained. The mass ratio of the aldehyde compound, polyamine, hydrogen-containing silicone oil, and phenolic compound with double bond substituents is 9-15:30-85:28-52:26-61. The amount of catalyst used is 5-10 ppm of the reaction system. The polyamine is polyetheramine EDR-148, diethylenetriamine, ethylenediamine, propylenediamine, pentanediamine, 2-methylpentanediamine, hexamethylenediamine, or cyclohexanediamine. The aldehyde compound is a 37% formaldehyde aqueous solution or paraformaldehyde.

3. The preparation method of the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that... The catalyst is at least one of platinum-based catalysts, rhodium-based catalysts, and ruthenium-based catalysts.

4. The preparation method of the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that... The solvent is at least one selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-hexane, cyclohexane, petroleum ether, tetrahydrofuran, ethyl acetate, acetone, benzene, toluene, dichloromethane, chloroform, and dichloroethane.

5. The application of the organosilicon-modified amine epoxy curing agent of claim 1 in the bonding and sealing of moisture- and heat-resistant electronic packaging, underwater environment equipment and facilities.

6. The application of the organosilicon-modified amine epoxy curing agent according to claim 5 in the bonding and sealing of moisture- and heat-resistant electronic packaging and underwater environment equipment and facilities, characterized in that... The weight ratio of the curing agent to the epoxy resin is 18~40:100.

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