Organic silicon modified amine epoxy curing agent and preparation method thereof

Abstract

The invention discloses an organic silicon modified amine epoxy curing agent and a preparation method thereof.The curing agent structurally comprises organic silicon, phenol and amine structures, and the preparation method comprises the following steps that 1, phenolic compounds containing double-bond substituent groups, a catalyst and hydrogen-containing silicone oil are stirred and mixed to be uniform in the nitrogen atmosphere at the temperature of 50-75 DEG C, then the temperature is increased to 65-90 DEG C, a reaction is conducted for 4-6 h, cooling is conducted, and the organic silicon modified amine epoxy curing agent is obtained; then evaporating to remove the solvent to obtain organic silicon modified phenol; and (2) uniformly mixing polyamine, organic silicon modified phenol, an aldehyde compound and a solvent, uniformly stirring at 50-75 DEG C in a nitrogen atmosphere, then carrying out reflux reaction for 2-4 hours, and evaporating to remove the solvent to obtain the organic silicon modified amine epoxy curing agent. According to the invention, the problem of poor bonding performance of the epoxy adhesive in a humid or underwater environment is solved, the bonding performance of the epoxy adhesive in underwater environments such as seawater and fresh water is effectively improved, and technical support can be provided for bonding and sealing of damp-heat-resistant electronic packaging, deep sea underwater marine equipment and facilities.

Description

Technical Field

[0001] The present invention relates to an epoxy adhesive, in particular to an organosilicon-modified amine epoxy curing agent and a preparation method thereof. Background Art

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

[0003] However, epoxy resin is inherently brittle and hygroscopic. When it absorbs water, it expands and cracks due to the evaporation of water. This leads to insufficient underwater curing and deterioration of performance, limiting its use in applications such as electronic packaging and deep-sea exploration.

[0004] Epoxy curing agents are a key factor influencing the bonding performance of epoxy adhesives. Currently, the predominantly amine-based curing agents used in the market are amine-based. In humid or underwater environments, polar groups like amino groups have a strong affinity for water, leading to poor interaction between polar groups at the interface between the adhesive and the substrate. This results in poor bonding performance in humid or underwater environments, preventing ideal adhesion. Therefore, modifying epoxy curing agents to meet the requirements for moisture-heat-resistant electronic packaging and underwater curing is particularly urgent. Summary of the Invention

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

[0006] The purpose of the present invention is achieved through the following technical solutions: A silicone-modified amine epoxy curing agent, which is composed of silicone, phenol, and amine structures, and its chemical structure is as follows: In the formula, R1 is a C2~C8 fatty chain alkyl or alicyclic alkyl, R2 is CH3-, C2H5- or Ph-, and R3 is a C3~C 15 Fatty chain alkyl.

[0007] A method for preparing the above-mentioned organosilicon-modified amine epoxy curing agent comprises the following steps: Step (1) stirring and mixing a phenolic compound containing a double bond substituent, a catalyst and a hydrogenated silicone oil at 50-75° C. in a nitrogen atmosphere, heating to 65-90° C. for reaction for 4-6 hours, and then evaporating and removing the solvent to obtain an organosilicon-modified phenol; Step (2) The polyamine, organosilicon-modified phenol, aldehyde compound and solvent are mixed and stirred uniformly at 50-75° C. under a nitrogen atmosphere, followed by reflux reaction for 2-4 hours, and the solvent is evaporated to obtain an organosilicon-modified amine epoxy curing agent, wherein: 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; The catalyst is at least one of a platinum-based catalyst, a rhodium-based catalyst, and a ruthenium-based catalyst, and the amount used is 5 to 10 ppm of the reaction system; The aldehyde compound is at least one of a 37% by mass formaldehyde solution, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, benzaldehyde, and furfural; The polyamine is at least one of polyetheramine EDR-148, diethylenetriamine, ethylenediamine, propylenediamine, pentamethylenediamine, 2-methylpentamethylenediamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, and cyclohexanediamine; 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 methylethyl hydrogen-containing silicone oil; The phenolic compound containing a double bond substituent is at least one of 3-allylphenol, 4-allylphenol, 4-(2-methyl-2-allyl)phenol, and cardanol; The solvent is at least one of 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.

[0008] The above-mentioned silicone-modified amine epoxy curing agent can be used in moisture-heat-resistant electronic packaging, and the bonding and sealing fields of underwater equipment and facilities in marine, freshwater and other underwater environments. When used, the ratio of epoxy resin to curing agent is 100:18~40 by weight.

[0009] Compared with the prior art, the present invention has the following advantages: The present invention introduces an organosilicon-modified phenol structure into polyamines through the Mannich reaction to prepare an organosilicon-modified amine epoxy curing agent. Compared with traditional epoxy curing agents, the advantages of this epoxy curing agent are: the organosilicon chain segment contained therein can significantly improve the toughness of the cured product, improve stress dispersion, and at the same time improve the moisture and heat resistance of the cured product; this curing agent can not only cure epoxy resin at room temperature, but also achieve underwater curing and bonding. The phenol structure contained therein can enhance the bonding with the interface and improve the underwater bonding performance. This curing agent can not only be used for moisture and heat resistant electronic packaging, but can also be used for bonding and sealing in underwater environments such as oceans and fresh water, solving the technical problem of poor bonding performance of epoxy adhesives in underwater environments, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the infrared spectrum of the organosilicon-modified amine epoxy curing agent prepared in Example 1; Figure 2 This is a scanning electron microscope image of the organosilicon-modified amine epoxy curing agent cured product prepared in Example 1. DETAILED DESCRIPTION

[0011] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0012] Example 1 Step 1) 61 parts of cardanol, 0.03 parts of platinum catalyst and 52 parts of phenyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol CAD.

[0013] 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. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields organosilicon-modified amine epoxy curing agent S-148, the structure of which is shown below: .

[0014] Example 2 Step 1) 61 parts of cardanol, 0.03 parts of platinum catalyst and 52 parts of phenyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol CAD.

[0015] Step 2) Mix 51 parts of diethylenetriamine (DETA), 100 parts of organosilicon-modified phenol (CAD), 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields the organosilicon-modified amine epoxy curing agent S-DETA, the structure of which is shown below: .

[0016] Example 3 Step 1) 61 parts of cardanol, 0.03 parts of platinum catalyst and 52 parts of phenyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol CAD.

[0017] Step 2) Mix 37 parts of 1,3-propylenediamine (PDA), 100 parts of organosilicon-modified phenol (CAD), 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields the organosilicon-modified amine epoxy curing agent S-PDA, the structure of which is shown below: .

[0018] Example 4 Step 1) 27 parts of 3-allylphenol, 0.01 parts of platinum catalyst and 52 parts of phenyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol AMC.

[0019] 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. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields organosilicon-modified amine epoxy curing agent S-148-2, the structure of which is shown below: .

[0020] Example 5 Step 1) 41 parts of 3-allylphenol, 0.02 parts of platinum catalyst and 42 parts of methyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol MMC.

[0021] Step 2) Mix 63 parts of diethylenetriamine (DETA), 82 parts of organosilicon-modified phenol MMC, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields organosilicon-modified amine epoxy curing agent S-DETA-2, the structure of which is shown below: .

[0022] Example 6 Step 1) 27 parts of 4-allylphenol, 0.01 parts of platinum catalyst and 52 parts of methyl hydrogen silicone oil were stirred and mixed uniformly at 60°C under a nitrogen atmosphere, and then heated to 80°C for reaction for 5 hours, and then evaporated to remove the solvent to obtain organosilicon-modified phenol PMMC.

[0023] Step 2) Mix 37 parts of 1,3-propylenediamine (PDA), 67 parts of organosilicon-modified phenol PMMC, 15 parts of paraformaldehyde, and an appropriate amount of anhydrous ethanol. Stir thoroughly at 60°C under a nitrogen atmosphere, then reflux for 3 hours. Evaporation of the solvent yields organosilicon-modified amine epoxy curing agent S-PDA-2, the structure of which is shown below: .

[0024] Application Example 1 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 epoxy resin in ratios 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, respectively.

[0025] Step 2) According to GB / T 1040.2-2022, rectangular low-carbon Q235 steel sheets with a sample size of 100 mm × 25 mm × 2 mm were selected. Two 0.2 mm diameter copper wires were arranged in parallel as a spacer layer, and the thickness of the epoxy resin cured layer in the overlap area of ​​the sample was precisely controlled to 0.2 mm to prepare a single-lap joint specimen. According to GB / T 1040.2-2022, dumbbell-shaped epoxy resin cured specimens were prepared using a standard mold. According to GB / T 1843-2008, unnotched epoxy resin cured specimens with a sample size of 80 mm × 10 mm × 4 mm were prepared.

[0026] Step 3) Tensile properties of dumbbell-shaped specimens were tested according to GB / T 1040.2-2022. Single-lap tensile shear strength tests were conducted on single-lap specimens according to GB / T 1040.2-2022. Impact resistance of unnotched epoxy resin cured specimens was measured according to GB / T 1843-2008. Five parallel specimens were prepared for each of these experiments. After five consecutive valid tests, the arithmetic mean of the strength values ​​was taken as the final result. Specific performance values ​​are shown in Table 1.

[0027] Table 1 Mechanical properties of epoxy resin cured products Application Example 2 Step 1) The organosilicon-modified amine epoxy curing agent S-148 prepared in the example and the bisphenol A epoxy resin E-51 were mixed in a ratio of 40:100 and cured at 90° C. for 2 h to obtain the epoxy resin cured product S-148 / E51.

[0028] Step 2) According to GB / T 1040.2-2022, a rectangular low-carbon Q235 steel sheet with a specimen size of 100 mm × 25 mm × 2 mm was selected. Two 0.2 mm diameter copper wires were arranged in parallel as a spacer layer, and the thickness of the epoxy resin cured layer in the specimen overlap area was precisely controlled to 0.2 mm to prepare a single overlap specimen.

[0029] Step 3) Using a temperature and humidity test chamber maintained at a constant temperature of (85 ± 2)°C and relative humidity of (85 ± 5)%, accelerated damp-heat aging testing was conducted on single-lap joint Q235 mild steel specimens for 42 consecutive days. The tensile shear strength was measured at four time points (0d, 14d, 28d, and 42d). Specific properties are shown in Table 2.

[0030] Table 2 Moisture-heat aging resistance of epoxy resin cured products Application Example 3 Step 1) Immerse a rectangular Q235 mild steel sheet measuring 100 mm × 25 mm × 2 mm in deionized water or seawater at 25°C. Then, evenly apply adhesive systems S-148 / E51, S-DETA / E51, and S-PDA / E51, respectively, consisting of an epoxy curing agent and epoxy resin containing 20 wt% calcium oxide filler, to the Q235 mild steel sheet. The two sheets are then butt-bonded underwater, secured with pressure using a clamp, and then cured underwater at 25°C for 7 days.

[0031] Step 2) After 7 days of underwater curing, the bonded steel sheets were removed from the water and cleaned. According to GB / T 1040.2-2022, a tensile shear test was performed within 2 hours to test the tensile shear strength. Specific performance is shown in Table 3.

[0032] Table 3 Underwater bonding performance of epoxy adhesive system The present invention introduces an organosilicon-modified phenol structure into polyamines through the Mannich reaction to prepare an organosilicon-modified amine epoxy curing agent. The epoxy adhesive bonded by curing the organosilicon-modified amine epoxy curing agent prepared by the present invention has good mechanical properties and a high shear strength retention rate under wet and hot conditions. The shear strength can reach up to 16.8 MPa in deionized water and up to 15.6 MPa in seawater. This shows that the epoxy adhesive prepared by the curing agent can be used in the fields of wet and heat-resistant electronic packaging, and the bonding and sealing of equipment and facilities in underwater environments such as oceans and freshwater, and has broad application prospects.

Claims

1. A silicone 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 fatty chain alkyl or alicyclic alkyl, R2 is CH3-, C2H5- or Ph-, and R3 is a C3~C 15 Fatty chain alkyl.

2. A method for preparing the organosilicon-modified amine epoxy curing agent according to claim 1, characterized in that The method comprises the following steps: Step (1) stirring and mixing a phenolic compound containing a double bond substituent, a catalyst and a hydrogenated silicone oil at 50-75° C. in a nitrogen atmosphere, heating to 65-90° C. for reaction for 4-6 hours, and then evaporating and removing the solvent to obtain an organosilicon-modified phenol; Step (2) uniformly mix the polyamine, organosilicon-modified phenol, aldehyde compound and solvent, stir evenly at 50-75° C. under a nitrogen atmosphere, then reflux for 2-4 hours, and evaporate to remove the solvent to obtain an organosilicon-modified amine epoxy curing agent, wherein the mass ratio of the aldehyde compound, polyamine, hydrogen-containing silicone oil and phenol compound containing double bond substituents is 9-15:30-85:28-52:26-61, and the amount of the catalyst is 5-10 ppm of the reaction system.

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 a platinum-based catalyst, a rhodium-based catalyst, and a ruthenium-based catalyst.

4. The method for preparing the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that The aldehyde compound is at least one of a 37% by mass formaldehyde aqueous solution, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, benzaldehyde, and furfural.

5. The method for preparing the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that The polyamine is at least one of polyetheramine EDR-148, diethylenetriamine, ethylenediamine, propylenediamine, pentamethylenediamine, 2-methylpentamethylenediamine, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, and cyclohexanediamine.

6. The method for preparing the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that 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 methylethyl hydrogen-containing silicone oil.

7. The method for preparing the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that The phenolic compound containing a double bond substituent is at least one of 3-allylphenol, 4-allylphenol, 4-(2-methyl-2-allyl)phenol, and cardanol.

8. The method for preparing the organosilicon-modified amine epoxy curing agent according to claim 2, characterized in that The solvent is at least one of 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.

9. Use of the organosilicon-modified amine epoxy curing agent according to claim 1 in the bonding and sealing of moisture-heat-resistant electronic packaging and underwater environment equipment and facilities.

10. Use of the organosilicon-modified amine epoxy curing agent according to claim 9 in the bonding and sealing of moisture-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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