High-temperature-resistant and high-toughness epoxy resin adhesive and preparation method thereof

Abstract

The present application relates to the technical field of adhesive, in particular to a kind of high-temperature-resistant high-toughness epoxy resin adhesive and preparation method thereof.The adhesive comprises the following raw materials by weight: epoxy resin 60-80 parts, curing agent 15-25 parts, toughening agent 5-15 parts, accelerator 0.1-1 part, coupling agent 0.1-1 part, thixotropic agent 0.5-2 parts, active diluent 10-20 parts, filler 20-40 parts.Epoxy resin is composed of biphenyl epoxy resin and naphthalene ring epoxy resin;Toughening agent is composed of epoxy group terminated core-shell rubber and amine end group polyimide oligomer;Filler is boron nitride and nano alumina.Preparation method includes mixing and dispersing each component and then vacuum degassing.The adhesive of the present application does not reduce high-temperature resistance while toughening, room temperature shear strength ≥21.5MPa, 250℃ shear strength ≥11.2MPa, impact strength ≥14.8kJ / m², glass transition temperature ≥187℃, and is suitable for electronic component packaging and industrial equipment installation.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a high-temperature resistant and high-toughness epoxy resin adhesive and its preparation method. Background Technology

[0002] Epoxy resin adhesives are widely used in industrial and daily life due to their excellent adhesion, mechanical properties, and chemical corrosion resistance. The development of modern science and technology in aviation, aerospace, and electronics has placed higher demands on the temperature resistance of adhesives. In addition to basic adhesive strength, high-temperature resistant adhesives must also possess the following comprehensive performance requirements: good thermophysical and chemical properties, high heat distortion, thermal decomposition, and thermogravimetric temperatures; good processability; maintaining original performance even after prolonged exposure to high temperatures under operating conditions; good heat resistance under cyclic temperature changes, and the ability to withstand high temperatures for short periods.

[0003] Traditional epoxy resin adhesives mostly use low-crosslinking epoxy resins, which can no longer meet the high-temperature resistance requirements of electronic products. Currently, high-temperature resistant epoxy resin adhesives prepared from multifunctional epoxy resins have been developed. Due to their high crosslinking degree and numerous epoxy groups, they possess good high-temperature resistance. However, the high crosslinking density makes these adhesives brittle, significantly reducing their toughness. Furthermore, these high-temperature resistant epoxy resin adhesives have poor impact resistance after curing and are extremely prone to breakage, thus greatly limiting their bonding performance and application. Therefore, there is an urgent need to develop an epoxy resin adhesive that combines high toughness and high-temperature resistance.

[0004] To address the above problems, this invention provides a high-temperature resistant and high-toughness epoxy resin adhesive and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant and high-toughness epoxy resin adhesive and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-temperature resistant and high-toughness epoxy resin adhesive, comprising the following raw materials in parts by weight: 60-80 parts epoxy resin; 15-25 parts curing agent; 5-15 parts toughening agent; 0.1-1 part accelerator; 0.1-1 part coupling agent; 0.5-2 parts thixotropic agent; 10-20 parts reactive diluent; and 20-40 parts filler. The epoxy resin is composed of biphenyl epoxy resin and naphthalene epoxy resin; the toughening agent is composed of epoxy-terminated core-shell rubber and amine-terminated polyimide oligomer; the curing agent is composed of 4,4'-diaminodiphenyl sulfone and m-phenylenediamine; the filler is boron nitride and nano-alumina; and the coupling agent is KH560 and KH590.

[0007] In a more optimized manner, the epoxy resin is composed of biphenyl epoxy resin TaiLuck-YX4000H and naphthalene epoxy resin NE-1001 in a weight ratio of (55-65):(15-25).

[0008] More optimally, the toughening agent is a toughening agent containing a core-shell structure or an amine-terminated toughening agent, composed of epoxy-terminated core-shell rubber NX-9000 and amine-terminated polyimide oligomer SW-PI-2000 in a weight ratio of (6-8):(2-4).

[0009] In a more optimized manner, the curing agent is composed of 4,4'-diaminodiphenyl sulfone and m-phenylenediamine in a weight ratio of (4-6):(2-3).

[0010] In a more optimized manner, the filler is composed of boron nitride and nano-alumina in a weight ratio of (12-18):(3-5).

[0011] In a more optimized manner, boron nitride needs to undergo surface treatment before use: mix boron nitride, coupling agent, and anhydrous ethanol at a weight ratio of (50-200):1:10, stir at high speed of 1500-2000 rpm for 2 hours, and then dry at 105℃.

[0012] A more optimized approach is to first mix the coupling agent with anhydrous ethanol and then with boron nitride.

[0013] Ideally, the isothermal grafting reaction temperature is 40-50 degrees Celsius.

[0014] In a more optimized manner, the coupling agents are KH560 and KH590 in a weight ratio of (3-4):(1-1.5).

[0015] In a more optimized manner, the accelerator is 2-phenylimidazole, the thixotropic agent is silica (model TS-720), and the reactive diluent is o-tolyl glycidyl ether.

[0016] This invention also provides a method for preparing a high-temperature resistant epoxy resin adhesive, comprising the following steps: First, the curing agents 4,4'-diaminodiphenyl sulfone and m-phenylenediamine are pulverized using a high-speed pulverizer and passed through a 100-mesh sieve.

[0017] The biphenyl epoxy resin was heated to 90 degrees Celsius and liquefied.

[0018] Naphthalene ring epoxy resin, composite coupling agent, reactive diluent, toughening agent, accelerator, filler, and thixotropic agent are slowly added to the liquefied biphenyl epoxy resin and mixed and dispersed.

[0019] After cooling the adhesive to room temperature, add the composite curing agent to disperse it, and then degas under vacuum to obtain the epoxy resin adhesive.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention employs a rigid-structured naphthalene-cyclic epoxy resin compounded with a biphenyl epoxy resin to improve temperature resistance while maintaining a certain level of toughness. It also uses an epoxy-terminated core-shell rubber compounded with an amine-terminated polyimide oligomer to toughen the material without lowering the glass transition temperature. The filler is a compound of surface-treated boron nitride and nano-alumina to further enhance temperature resistance. This adhesive can be used long-term at temperatures above 200°C, maintaining high shear strength and impact strength at high temperatures, making it suitable for electronic component packaging and aerospace bonding.

[0021] In this invention, biphenyl epoxy resin primarily provides strength and temperature resistance in the adhesive, while naphthalene epoxy resin primarily provides toughness. PI oligomers are added to balance heat resistance. Furthermore, by using a composite curing agent that combines a medium-temperature curing agent and a high-temperature curing agent, the strength and heat resistance of the adhesive are synergistically enhanced, resulting in superior overall mechanical properties.

[0022] The adhesive of this invention toughens without reducing high-temperature resistance, with a room temperature shear strength ≥21.5MPa, a 250℃ shear strength ≥11.2MPa, an impact strength ≥14.8kJ / m², and a glass transition temperature ≥187℃. It is suitable for electronic component packaging and industrial equipment installation. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The effectiveness of this invention is verified through several embodiments and comparative examples. Example 1

[0025] A high-temperature resistant and high-toughness epoxy resin adhesive comprises the following raw materials in parts by weight: 70 parts epoxy resin; 20 parts curing agent; 10 parts toughening agent; 0.5 parts accelerator; 0.5 parts coupling agent; 1 part thixotropic agent; 15 parts reactive diluent; and 30 parts filler.

[0026] The epoxy resin is composed of biphenyl epoxy resin TaiLuck-YX4000H and naphthalene epoxy resin NE-1001 in a weight ratio of 60:10. The curing agent is composed of 4,4'-diaminodiphenyl sulfone and m-phenylenediamine in a weight ratio of 12:8. The toughening agent is composed of epoxy-terminated core-shell rubber NX-9000 and amine-terminated polyimide oligomer SW-PI-2000 in a weight ratio of 7:3. The accelerator is 2-phenylimidazolium. The coupling agent is composed of KH560 and KH590 in a weight ratio of 4:1. The thixotropic agent is TS-720 silica. The reactive diluent is o-tolyl glycidyl ether. The filler is composed of boron nitride and nano-alumina in a weight ratio of 15:5. The boron nitride filler requires surface treatment before use. The specific operation is as follows: Boron nitride, coupling agent and anhydrous ethanol are mixed in a weight ratio of 200:1:10, stirred at high speed of 2000 rpm for 2 hours and then dried at 105℃ to obtain the treated boron nitride.

[0027] Preparation method: First, pulverize the curing agents 4,4'-diaminodiphenyl sulfone and m-phenylenediamine using a high-speed pulverizer and pass them through a 100-mesh sieve; The biphenyl epoxy resin was liquefied by heating it to 90°C. Naphthalene ring epoxy resin, composite coupling agent, reactive diluent, toughening agent, accelerator, filler, and thixotropic agent are slowly added to the liquefied biphenyl epoxy resin and mixed and dispersed. After cooling to room temperature, add curing agent to disperse, then degas under vacuum to obtain the finished product. Example 2

[0028] The difference from Example 1 is that the epoxy resin adhesive contains the following raw materials in parts by weight: epoxy resin: 70 parts; curing agent: 20 parts; toughening agent: 10 parts; accelerator: 0.5 parts; coupling agent: 0.5 parts; thixotropic agent: 1 part; reactive diluent: 15 parts; filler: 30 parts; The epoxy resin is composed of biphenyl epoxy resin TaiLuck-YX4000H and naphthalene epoxy resin NE-1001 in a weight ratio of 50:20. The curing agent is composed of 4,4'-diaminodiphenyl sulfone and m-phenylenediamine in a weight ratio of 12:8. The toughening agent is composed of epoxy-terminated core-shell rubber NX-9000 and amine-terminated polyimide oligomer SW-PI-2000 in a weight ratio of 7:3. The accelerator is 2-phenylimidazolium. The coupling agent is composed of KH560 and KH590 in a weight ratio of 4:1.

[0029] The thixotropic agent is TS-720 silica. The reactive diluent is o-tolyl glycidyl ether. The filler is composed of boron nitride and nano-alumina in a weight ratio of 15:5. Before use, the boron nitride filler requires surface treatment. The specific procedure is as follows: mix boron nitride, coupling agent, and anhydrous ethanol in a weight ratio of 200:1:10, stir at high speed for 2 hours, and then dry at 105℃ to obtain the treated boron nitride.

[0030] The specific operating steps are the same as in Example 1.

[0031] Comparative Example 1 The difference from Example 1 is that the filler is only nano-alumina (without boron nitride), and the filler is not surface treated.

[0032] Comparative Example 2 The difference from Example 1 is that the epoxy resin is only naphthalene ring epoxy resin NE-1001.

[0033] Comparative Example 3 The difference from Example 1 is that the toughening agent is only epoxy-terminated core-shell rubber NX-9000.

[0034] Comparative Example 4 The difference from Example 1 is that the curing agent is only 4,4'-diaminodiphenyl sulfone.

[0035] Comparative Example 5 The difference from Example 1 is that boron nitride is not surface treated.

[0036] Test methods The epoxy resin adhesive prepared in the example was evenly applied to the stainless steel substrate that had been wiped with alcohol to make a dynamic shearing strip. The stainless steel substrate had a size of 25*100*2mm and a bonding area of ​​25*12mm. The thickness of the adhesive layer was controlled by a 0.12mm iron wire on the bonding surface.

[0037] The epoxy resin adhesive prepared in the example was evenly applied to an alcohol-wiped stainless steel substrate to create an impact test piece. The stainless steel substrate had dimensions of 80±2mm in length, 10.0±0.2mm in width, and 4.0±0.2mm in thickness. A 0.12mm wire was used to control the adhesive layer thickness on the bonding surface.

[0038] The prepared shear and impact samples were then cured under the following conditions: 85℃ for 2 hours, 155℃ for 2.5 hours, and 180℃ for 1 hour.

[0039] Test method: Shear strength, impact strength, glass transition temperature, and thermogravimetric properties were tested according to standards such as ASTM D2295 and GB / T1043.1-2008.

[0040] Shear strength was tested at 25°C and 250°C, and after being placed at 200°C for 1000 hours. The testing standard was ASTM D2295. At least 5 specimens were tested in each group, and the arithmetic mean was taken. The testing instrument was an Instron™ 68-30.

[0041] Impact strength was tested using a pendulum impact test at room temperature. The impact strength was determined according to GB / T 1043.1-2008. The testing instrument was an HD-R802 digital display impact testing machine. Unnotched simply supported beam specimens were used. The specimen size was 80 mm × 10 mm × 4 mm with a span of 62 mm. The test temperature was 25℃. Each group of tests consisted of no less than 5 specimens. The arithmetic mean was taken, and the unit was kJ / m².

[0042] Glass transition temperature: The glass transition temperature (Tg) was determined according to GB / T 19466.2-2004 using a differential scanning calorimeter (DSC). The testing instrument was a TA-DSC25, the atmosphere was nitrogen, the heating rate was 10 ℃ / min, the test temperature range was 25~300 ℃, and the test was performed twice. The glass transition temperature was determined by the second heating curve.

[0043] Thermogravimetric analysis (TGA): The thermogravimetric analysis was performed according to GB / T 27761-2011 using a TA-Discovery TGA 550 nitrogen atmosphere. The heating rate was 10℃ / min, and the test range was 30~600℃. The 5% thermogravimetric temperature and the mass retention rate at 200℃ and 300℃ were recorded.

[0044] The results are shown in Table 1:

[0045] As shown in Table 1, the epoxy resin adhesive of the present invention has a shear strength of 21.5 MPa at room temperature, a shear strength of 11.2 MPa at 250°C, a shear strength of 18.3 MPa after aging at 200°C for 1000 hours, an impact strength of 14.8 MPa, a TG of 187°C, a temperature of 389°C with 5% thermal weight loss, a mass retention rate of 98.6% at 200°C, and a mass retention rate of 92.2% at 300°C.

[0046] Furthermore, comparing Comparative Example 1 and Example 1, it can be seen that when other formulation components remain unchanged, and the filler is replaced with Al2O3 alone, the adhesive strength and toughness of the adhesive both decrease, and the high-temperature performance also decreases. This indicates that when BN is removed, the heat resistance of the adhesive decreases, and the interfacial adhesion also decreases.

[0047] Comparing Comparative Example 2 and Example 1, it can be seen that when other formulations remain unchanged, the adhesive strength and high-temperature resistance of the adhesive decrease, while the impact strength increases when only naphthalene epoxy resin is used. This indicates that biphenyl epoxy resin mainly provides strength and temperature resistance in the adhesive, while naphthalene epoxy resin mainly provides toughness.

[0048] Comparing Comparative Example 3 and Example 1, it can be seen that when other formulation components remain unchanged, and the toughening agent is changed to a single core-shell rubber, the strength and temperature resistance of the adhesive decrease, while the impact strength increases. This indicates that the core-shell rubber has poor heat resistance and insufficient strength, requiring the addition of PI oligomers to balance its heat resistance.

[0049] Comparing Comparative Example 4 and Example 1, it can be seen that when other formulation components remain unchanged, using only 4,4'-diaminodiphenyl sulfone as the curing agent does not significantly alter the adhesive strength and temperature resistance, but it does cause a substantial decrease in impact strength. This indicates that using only 4,4'-diaminodiphenyl sulfone as the curing agent leads to brittleness and high internal stress in the adhesive.

[0050] Comparing Comparative Example 5 and Example 1, it can be seen that when other formulation components remain unchanged, the lack of surface treatment of filler BN leads to a significant decrease in the adhesive bond strength and impact strength. This indicates that the absence of surface treatment of BN results in poor interfacial bond strength, uneven mixing within the adhesive, and consequently, poor bulk strength.

[0051] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-temperature resistant and high-toughness epoxy resin adhesive, characterized in that: The high-temperature resistant epoxy resin adhesive comprises the following raw materials in parts by weight: Epoxy resin: 60-80 parts; Curing agent: 15-25 parts; Toughening agent: 5-15 parts; Accelerator: 0.1-1 part; Coupling agent: 0.1-1 part; Thixotropic agent: 0.5-2 parts; reactive diluent: 10-20 parts; filler: 20-40 parts; The epoxy resin is composed of biphenyl epoxy resin and naphthalene epoxy resin; the toughening agent is composed of epoxy-terminated core-shell rubber and amine-terminated polyimide oligomer.

2. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The epoxy resin is composed of biphenyl epoxy resin TaiLuck-YX4000H and naphthalene epoxy resin NE-1001 in a weight ratio of (50-60):(10-20).

3. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The toughening agent is composed of epoxy-terminated core-shell rubber NX-9000 and amine-terminated polyimide oligomer SW-PI-2000 in a weight ratio of (6-8):(2-4).

4. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The curing agent is composed of 4,4'-diaminodiphenyl sulfone and m-phenylenediamine in a weight ratio of (3-5):(2-3).

5. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The accelerator is 2-phenylimidazole.

6. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The filler is composed of boron nitride and nano-alumina in a weight ratio of (12-18):(3-5).

7. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The coupling agent is composed of KH560 and KH590 in a weight ratio of (3-4):(1-1.5).

8. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 1, characterized in that: The boron nitride filler needs to be surface treated before use. The specific operation is as follows: mix boron nitride, coupling agent and anhydrous ethanol in a weight ratio of (50-200):1:10, stir at high speed of 1500-2000 rpm for 2 hours and then dry at 105℃ to obtain the treated boron nitride.

9. The high-temperature resistant and high-toughness epoxy resin adhesive according to claim 8, characterized in that: The mixing method in the surface treatment is to first mix the coupling agent with anhydrous ethanol and then add it dropwise to boron nitride.

10. A method for preparing a high-temperature resistant and high-toughness epoxy resin adhesive, used to prepare any one of the high-temperature resistant and high-toughness epoxy resin adhesives as described in claims 1-9, characterized in that, Includes the following steps: First, the epoxy resin and toughening agent of the formula are heated and stirred to disperse, then cooled to room temperature. Then, they are mixed with the coupling agent, curing agent, accelerator, filler, reactive diluent and thixotropic agent of the formula and dispersed to obtain epoxy resin adhesive.

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